Human ESC-derived MSCs enhance fat engraftment by promoting adipocyte reaggregation, secreting CCL2 and mobilizing macrophages

Pluripotent stem cell-derived mesenchymal stem cells for therapeutic applications, developmental study, and cancer research

Human mesenchymal stem cells (MSCs) have been widely studied and applied for the treatment of various diseases due to their crucial role in tissue repair and regeneration. Compared to MSCs isolated from somatic tissues, MSCs differentiated from human pluripotent stem cells (ps-MSCs) have demonstrated similar therapeutic effects while possessing some advantages in quality control and assurance, given their unlimited and consistent supply of source cells. This makes ps-MSCs highly druggable and promising for therapeutic applications. In this minireview, we introduce the latest progress in ps-MSC research, focusing on the therapeutic properties, origin, in vivo development, and application of ps-MSCs in cancer research. We will also discuss the perspectives and challenges of this relatively new source of MSCs.

Mesenchymal Stromal Cells Increase the Natural Killer Resistance of Circulating Tumor Cells via Intercellular Signaling of cGAS-STING-IFNβ-HLA

Circulating tumor cells (CTCs) shed from primary tumors must overcome the cytotoxicity of immune cells, particularly natural killer (NK) cells, to cause metastasis. The tumor microenvironment (TME) protects tumor cells from the cytotoxicity of immune cells, which is partially executed by cancer-associated mesenchymal stromal cells (MSCs). However, the mechanisms by which MSCs influence the NK resistance of CTCs remain poorly understood. This study demonstrates that MSCs enhance the NK resistance of cancer cells in a gap junction-dependent manner, thereby promoting the survival and metastatic seeding of CTCs in immunocompromised mice. Tumor cells crosstalk with MSCs through an intercellular cGAS-cGAMP-STING signaling loop, leading to increased production of interferon-β (IFNβ) by MSCs. IFNβ reversely enhances the type I IFN (IFN-I) signaling in tumor cells and hence the expression of human leukocyte antigen class I (HLA-I) on the cell surface, protecting the tumor cells from NK cytotoxicity. Disruption of this loop reverses NK sensitivity in tumor cells and decreases tumor metastasis. Moreover, there are positive correlations between IFN-I signaling, HLA-I expression, and NK tolerance in human tumor samples. Thus, the NK-resistant signaling loop between tumor cells and MSCs may serve as a novel therapeutic target.

Developmental potency of human ES cell-derived mesenchymal stem cells revealed in mouse embryos following blastocyst injection

Mesenchymal stem cells (MSCs) are present in almost all the tissues in the body, critical for their homeostasis and regeneration. However, the stemness of MSCs is mainly an in vitro observation, and lacking exclusive markers for endogenous MSCs makes it difficult to study the multipotency of MSCs in vivo, especially for human MSCs. To address this hurdle, we injected GFP-tagged human embryonic stem cell (hESC)-derived MSCs (EMSCs) into mouse blastocysts. EMSCs survived well and penetrated both the inner cell mass and trophectoderm, correlating to the higher anti-apoptotic capability of EMSCs than hESCs. Injected EMSCs contributed to skeletal, dermal, and extraembryonic tissues in the resultant chimera and partially rescued skeletal defects in Sox9+/- mouse fetuses. Thus, this study provides evidence for the stemness and developmental capability of human MSCs through chimerization with the mouse blastocyst, serving as a model for studying human mesenchymal and skeletal development.

Pluronic F-127 Hydrogel Loaded with Human Adipose-Derived Stem Cell-Derived Exosomes Improve Fat Graft Survival via HIF-1α-Mediated Enhancement of Angiogenesis

Purpose

Autologous fat grafting is playing an increasingly important role in plastic surgery. However, high absorption and low survival of autologous fat grafts limit their clinical application. This study aimed to investigate whether human adipose-derived stem cell-derived exosomes (hASC-Exos) encapsulated in a PF-127 hydrogel can improve the survival of autologous fat grafts and to elucidate the underlying mechanisms.

Patients and Methods

Exosomes were isolated from hASCs and identified using transmission electron microscopy, nanoparticle tracking analysis and Western blotting. We performed functional assays in vitro to assess the effect of hASC-Exos on proliferation, migration, and tube formation as well as their regulatory role in the HIF-1α/VEGF signaling pathway. hASC-Exos encapsulated in the PF-127 hydrogel were used as an in vivo autologous fat graft model. The effects of the PF-127 hydrogel/hASC-Exos and the role of the HIF-1α/VEGF signaling pathway in promoting angiogenesis in an autologous fat grafting model were assessed.

Results

hASC-Exos were taken up by human umbilical vein endothelial cells and enhanced their proliferation, migration, and tubule formation in vitro. The effects of hASC-Exos on promoting angiogenesis were mediated by the HIF-1α/VEGF signaling pathway. Moreover, we fabricated a PF-127 hydrogel for the sustained release of hASC-Exos, and in vivo results showed that hASC-Exos encapsulated in PF-127 hydrogel improved the survival of autologous fat grafts.

Conclusion

Our findings indicated that hASC-Exos encapsulated in PF-127 hydrogel serve as a key regulator of angiogenesis by activating the HIF-1α/VEGF signaling pathway and provide a promising strategy for autologous fat grafting treatment.

miR-100a-5p-enriched exosomes derived from mesenchymal stem cells enhance the anti-oxidant effect in a Parkinson's disease model via regulation of Nox4/ROS/Nrf2 signaling

BACKGROUND

The pathogenesis of Parkinson's disease (PD) has not been fully elucidated, and there are no effective disease-modifying drugs for the treatment of PD. Mesenchymal stem cells have been used to treat several diseases, but are not readily available.

METHODS

Here, we used phenotypically uniform trophoblast stage-derived mesenchymal stem cells (T-MSCs) from embryonic stem cells, which are capable of stable production, and their exosomes (T-MSCs-Exo) to explore the molecular mechanisms involved in dopaminergic (DA) neuron protection in PD models using experimental assays (e.g., western blotting, immunofluorescence and immunohistochemistry staining).

RESULTS

We assessed the levels of DA neuron injury and oxidative stress in MPTP-induced PD mice and MPP+-induced MN9D cells after treating them with T-MSCs or T-MSCs-Exo. Furthermore, T-MSCs-Exo miRNA sequencing analysis revealed that miR-100-5p-enriched T-MSCs-Exo directly targeted the 3' UTR of NOX4, which could protect against the loss of DA neurons, maintain nigro-striatal system function, ameliorate motor deficits, and reduce oxidative stress via the Nox4-ROS-Nrf2 axis in PD models.

CONCLUSIONS

The study suggests that miR-100-5p-enriched T-MSCs-Exo may be a promising biological agent for the treatment of PD. Schematic summary of the mechanism underlying the neuroprotective actions of T-MSCs-Exo in PD. T-MSCs Exo may inhibit the expression level of the target gene NOX4 by delivering miR-100-5p, thereby reducing ROS production and alleviating oxidative stress via the Nox4-ROS-Nrf2 axis, thus improving DA neuron damage in PD.

Effect of miR-149-5p on intramuscular fat deposition in pigs based on metabolomics and transcriptomics

As one of the important traits in pig production, meat quality has important research significance and value. Intramuscular fat (IMF) content is one of the most important factors affecting pork quality. Many experimental studies have shown that IMF content is closely related to the flavor, tenderness, and juiciness of pork. Therefore, it is of great significance to study the mechanism of porcine IMF deposition. Previous research indicated that miR-149-5p promoted the proliferation of porcine intramuscular (IM) preadipocytes and decreased their ability to differentiate, albeit the exact mechanism of action is unknown. In vitro, foreign pigs showed increased miR-149-5p expression and reduced fat deposition when compared to Queshan Black pigs. This study conducted metabolomics and transcriptomics analyses of porcine IM preadipocytes overexpressing miR-149-5p to verify their effects on lipid formation. According to metabolomics analysis, the overexpression of miR-149-5p has significantly altered the lipid, organic acid, and organic oxygen metabolites of porcine IM preadipocytes. Specially speaking, it has changed 115 metabolites, including 105 up-regulated and 10 down-regulated ones, as well as the composition of lipid, organic acid, and organic oxygen metabolism-related metabolites. RNA-seq analysis showed that overexpression of miR-149-5p significantly altered 857 genes, of which 442 were up-regulated, and 415 were down-regulated, with enrichment to MAPK, IL-17, PI3K-Akt, and ErbB signaling pathways. We found that overexpression of miR-149-5p inhibited adipogenic differentiation by changing cAMP signaling pathway in porcine IM preadipocytes. In addition, the overexpression of miR-149-5p may affect the transport of Cu²⁺ by targeting ATP7A and inhibiting adipogenic differentiation. These findings elucidate the regulatory function of miR-149-5p in porcine IM preadipocytes, which may be a key target for controlling pork quality.

Revealing the mystery of persistent smell loss in Long COVID patients

COVID-19 is hopefully approaching its end in many countries as herd immunity develops and weaker strains of SARS-CoV-2 dominate. However, a new concern occurs over the long-term effects of COVID-19, collectively called "Long COVID", as some symptoms of the nervous system last even after patients recover from COVID-19. This review focuses on studies of anosmia, i.e., impairment of smell, which is the most common sensory defect during the disease course and is caused by olfactory dysfunctions. It remains mysterious how the olfactory functions are affected since the virus can't invade olfactory receptor neurons. We describe several leading hypotheses about the mystery in hope to provide insights into the pathophysiology and treatment strategies for anosmia.

Bone marrow mesenchymal stem cells enhance angiogenesis and promote fat retention in fat grafting via polarized macrophages

Background

Fat grafting is one of the most common soft tissue filling methods in plastic surgery. Bone marrow mesenchymal stem cell (BM-MSC) transplantation is an effective method for improving graft retention. However, the role of BM-MSCs in fat transplantation is not completely clear.

Methods

Human fat particles, together with BM-MSCs or PBS as a control, were subcutaneously transplanted into the backs of nude mice. Samples were taken on days 14, 30 and 90 post-grafting to calculate the fat graft retention rate, and tissue staining was evaluated. Furthermore, macrophages were treated with BM-MSC conditioned medium (BM-MSC-CM) to identify the beneficial component secreted by these stem cells.

Results

In this study, we found that BM-MSCs improved retention by enhancing angiogenesis in fat grafting. Further analysis revealed that BM-MSCs could significantly inhibit the expression of the proinflammatory M1 macrophage markers interleukin (IL)-1β, tumor necrosis factor-α (TNF-α) and IL-6 in the early stages of fat grafting and promote the expression of the anti-inflammatory M2 macrophage markers Arg1, IL-10 and VEGF. Furthermore, our results showed that IL-10 secreted by BM-MSCs induced M2 macrophage polarization in vitro.

Conclusions

BM-MSC transplantation can improve the fat retention rate and promote angiogenesis, which may be related to M2 macrophages. These results help elucidate the role of BM-MSCs in fat grafting.