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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Gastric cancer tissue-derived mesenchymal stem cells impact peripheral blood mononuclear cells via disruption of Treg/Th17 balance to promote gastric cancer progression

Highlights: • GC-MSCs educate PBMCs to promote gastric cancer progression. • GC-MSCs disrupt the Treg/Th17 balance in PBMCs. • GC-MSCs induce Treg cell differentiation and suppress Th17 cell proliferation. Gastric cancer tissue-derived mesenchymal stem cells (GC-MSCs) are important resident stromal cells in the tumor microenvironment (TME) and have been shown to play a key role in gastric cancer progression. Whether GC-MSCs exert a tumor-promoting function by affecting anti-tumor immunity is still unclear. In this study, we used GC-MSC conditioned medium (GC-MSC-CM) to pretreat peripheral blood mononuclear cells (PBMCs) from healthy donors. We found that GC-MSC-CM pretreatment markedly reversed the inhibitory effect of PBMCs on gastric cancer growth in vivo, but did not affect functions of PBMCs on gastric cancer cell proliferation, cell cycle and apoptosis in vitro. PBMCs pretreated with GC-MSC-CM significantly promoted gastric cancer migration and epithelial-mesenchymal transition in vitro and liver metastases in vivo. Flow cytometry analysis showed that GC-MSC-CM pretreatment increased the proportion of Treg cells and reduced that of Th17 cells in PBMCs. CFSE labeling and naïve CD4{sup +} T cells differentiation analysis revealed that GC-MSC-CM disrupted the Treg/Th17 balance in PBMCs by suppressing Th17 cell proliferation and inducing differentiation of Treg cells. Overall, our collective results indicate that GC-MSCs impair the anti-tumor immune response of PBMCs through disruption of Treg/Th17 balance, thus providing new evidence that gastric cancer tissue-derived MSCs contribute to the immunosuppressive TME.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Heme oxygenase-1 protects bone marrow mesenchymal stem cells from iron overload through decreasing reactive oxygen species and promoting IL-10 generation

Iron overload (IO) caused by frequent blood transfusion in hematological diseases has become a major concern. In this study, up-regulation of heme oxygenase-1 (HO-1), a protector against oxidative stress, was observed in bone marrow mesenchymal stem cells (BMMSCs) at the early stage of IO and had favorable prognosis in an IO mouse model. Given that the protective role of HO-1 in IO damage of BMMSCs was still unknown, the mechanism was explored in vitro and in vivo. BMMSCs were transfected with HO-1/siHO-1 in vitro, and the mouse model was established to further evaluate the effect of HO-1 on IO in vivo. As a result, HO-1 decreased the apoptotic rate of BMMSCs with IO through reducing intracellular reactive oxygen species (ROS) but increasing IL-10 secretion. In addition, IL-10 was mediated by HO-1 via the ERK pathway. Intracellular iron was down-regulated by hepcidin depending on IL-10. In conclusion, HO-1 protects BMMSCs from ROS by secreting IL-10 upon iron overload.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Mesenchymal stem cell exosomes promote immunosuppression of regulatory T cells in asthma

Highlights: • MSC exosomes promote Tregs proliferation by upregulating IL-10 and TGF-β1 in asthma. • MSC exosomes enhance immunosuppression capacity of Tregs from asthmatic patient. • The effect of MSC exosomes on Tregs may be mediated by APCs. Mesenchymal stem cells (MSCs) and regulatory T cells (Tregs) are both potent immune-modulators. The aberrant proliferation and function of Tregs plays an important role in the development of asthma. Our previous studies have demonstrated the role of MSCs in promoting proliferation and immune-modulating of Tregs, as well as alleviating airway inflammation of asthmatic mice. In the present study, we isolated exosomes secreted by MSCs and investigated their immunomodulation effect on peripheral blood mononuclear cells (PBMCs) of asthmatic patient. We found that MSC exosomes upregulated IL-10 and TGF-β1 from PBMCs, thus promoting proliferation and immune-suppression capacity of Tregs. Furthermore, antigen presenting cells (APCs) but not CD4+ T cells-dependent pathway was shown to be possible mechanism involved in MSC exosome-mediated regulation. Our data elucidated the key role of exosomes in immune-modulation of MSCs, and suggested the therapeutic potential of MSC exosomes for asthma.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Maintenance of hematopoietic stem and progenitor cells in fetal intra-aortic hematopoietic clusters by the Sox17-Notch1-Hes1 axis

Highlights: • IAHCs of E10.5 AGM co-express SOX17 and NOTCH1. • SOX17 directly binds to the Notch1 promoter and induces Notch1 expression. • Notch1- and Hes1-transduced HSCs and HPCs maintain their undifferentiated states. The aorta-gonad-mesonephros region, from which definitive hematopoiesis first arises in midgestation mouse embryos, has intra-aortic hematopoietic clusters (IAHCs) containing hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs). We previously reported expression of the transcription factor Sox17 in IAHCs, and overexpression of Sox17 in CD45{sup low}c-KIT{sup high} cells comprising IAHCs maintains the formation of cell clusters and their multipotency in vitro over multiple passages. Here, we demonstrate the importance of NOTCH1 in IAHC formation and maintenance of the HSC/HPC phenotype. We further show that Notch1 expression is positively regulated by SOX17 via direct binding to its gene promoter. SOX17 and NOTCH1 were both found to be expressed in vivo in cells of IAHCs by whole mount immunostaining. We found that cells transduced with the active form of NOTCH1 or its downstream target, Hes1, maintained their multipotent colony-forming capacity in semisolid medium. Moreover, cells stimulated by NOTCH1 ligand, Jagged1, or Delta-like protein 1, had the capacity to form multilineage colonies. Conversely, knockdown of Notch1 and Hes1 led to a reduction of their multipotent colony-forming capacity. These results suggest that the Sox17-Notch1-Hes1 pathway is critical for maintaining the undifferentiated state of IAHCs.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The three branches of the unfolded protein response exhibit differential significance in breast cancer growth and stemness

Highlights: • UPR sensors are highly expressed in cancers and correlate with SOX2 and OCT4. • Inhibition/silencing of PERK and ATF6α strongly affect breast cancer growth and CSC. • An appropriate UPR level is required for the mammosphere formation and maintenance. • UPR and pluripotency pathways interact and influence each other. • C/EBPδ interacts with SOX2 and UPR transcription factors, modulating both pathways. The unfolded protein response (UPR) is widely activated in cancers. The mammalian UPR encompasses three signaling branches, namely inositol-requiring enzyme-1α (IRE1α), protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) and activating transcription factor 6α (ATF6α). The functional significance of each branch in tumorigenesis is incompletely understood, especially in cancer stem cells (CSCs). Here, we report that inhibition and silencing of the three UPR sensors has differential effects on breast cancer growth and the CSC population. The levels of PERK and ATF6α strongly correlate with the expression of sex determining region Y (SRY)-box 2 (SOX2), a pluripotency regulator, in human breast cancer tissues. UPR activation is also elevated in the CSC-enriched mammospheres. Inhibition of the UPR sensors or excess ER stress markedly reduces the formation and maintenance of mammospheres, suggesting that an appropriate level of UPR activation is critical for the CSC survival. Mechanistically, transcription factors from UPR and pluripotency pathways interact and reciprocally influence each other. A transcription modulator, CCAAT-enhancer-binding protein delta (C/EBPδ), interacts with pluripotency regulator, SOX2, and UPR transcription factors, thus likely serving as a link to coordinate UPR and pluripotency maintenance in CSCs. Our findings demonstrate that UPR is critical for both cancer growth and pluripotency, and highlight the differential role and complexity of the three UPR branches in tumorigenesis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Rosiglitazone rescues human neural stem cells from amyloid-beta induced ER stress via PPARγ dependent signaling

Highlights: • Rosiglitazone rescued the Aβ decreased hNSCs survivability. • Rosiglitazone normalized ER stress in the hNSCs with Aβ. • Rosiglitazone improved ER and mitochondrial homeostasis in the hNSCs with Aβ. Peroxisome proliferator-activated receptor gamma (PPARγ) belongs to a family of ligand-activated nuclear receptors known to regulate many crucial physiological and pathological conditions. Indeed, altered PPARγ transcriptional activity contributes to metabolic syndromes (obesity and hyperglycemia associated with type 2 diabetes mellitus), stroke and neurodegenerative diseases. Various studies suggest that PPARγ agonists influence neuronal deficits in Alzheimer's Disease (AD) patients and rodent models of AD. Expression of amyloid-beta (Aβ), a neuropathological marker associated with the pathogenesis of AD neuronal impairment, is inversely correlated with the activation of PPARγ-dependent neuroprotective responses. Nevertheless, molecular mechanisms by which the effects of PPARγ agonists in AD remain to be clarified. Here, we explore the PPARγ signaling pathways and networks that protect against Aβ-induced endoplasmic reticulum (ER) stress (e.g., caspase 4, Bip, CHOP, ASK1 and ER calcium), cell death (e.g., viability and cytochrome c) and mitochondrial deficiency (e.g., maximal respiratory function, COX activity, and mitochondrial membrane potential) events in the human neural stem cells (hNSCs) treated with Aβ. Co-treatment with GW9662 (an antagonist of PPARγ) effectively blocked these protective effects by rosiglitazone, providing strong evidence that PPARγ-dependent signaling rescues hNSCs from Aβ-mediated toxicity. Together, our data suggest activation of PPARγ pathway might be critical to protecting against AD-related ER stress, ER disequilibrium and mitochondrial deficiency. These findings also improve our understanding of the role of PPARγ in hNSCs, and may aid in the development and implementation of new therapeutic strategies for the treatment of AD.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Cell-free therapy based on adipose tissue stem cell-derived exosomes promotes wound healing via the PI3K/Akt signaling pathway

Highlights: • ADSC-Exos are internalized into HDFs and regulate their biological behaviors and functions. • ADSC-Exos play an important role in accelerating wound healing via activating PI3K/Akt signaling pathway. • ADSC-Exos may serve as a cell-free therapy for the potential clinical treatment of wound healing. Adipose tissue-derived stem cells (ADSCs) have been shown to enhance wound healing via their paracrine function. Exosomes, as one of the most important paracrine factors, play an essential role in this process. However, the concrete mechanisms that underlie this effect are poorly understood. In this study, we aim to explore the potential roles and molecular mechanisms of exosomes derived from ADSCs in cutaneous wound healing.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

3D-cultured neural stem cell microarrays on a micropillar chip for high-throughput developmental neurotoxicology

Highlights: • Optimum cell viability and spheroid formation observed in 3D cultured NSC microarrays. • Lentiviruses constructed for measuring the expression levels of NSC biomarkers. • Differentiation of ReNcell VM assessed after growth factor removal and with additives. • High-throughput assessment of self-renewal and differentiation demonstrated in 3D cell culture. Numerous chemicals including environmental toxicants and drugs have not been fully evaluated for developmental neurotoxicity. A key gap exists in the ability to predict accurately and robustly in vivo outcomes based on in vitro assays. This is particularly the case for predicting the toxicity of chemicals on the developing human brain. A critical need for such in vitro assays is choice of a suitable model cell type. To that end, we have performed high-throughput in vitro assessment of proliferation and differentiation of human neural stem cells (hNSCs). Conventional in vitro assays typically use immunofluorescence staining to quantify changes in cell morphology and expression of neural cell-specific biomarkers, which is often time-consuming and subject to variable specificities of available antibodies. To alleviate these limitations, we developed a miniaturized, three-dimensional (3D) hNSC culture with ReNcell VM on microarray chip platforms and established a high-throughput promoter-reporter assay system using recombinant lentiviruses on hNSC spheroids to assess cell viability, self-renewal, and differentiation. Optimum cell viability and spheroid formation of 3D ReNcell VM culture were observed on a micropillar chip over a period of 9 days in a mixture of 0.75% (w/v) alginate and 1 mg/mL growth factor reduced (GFR) Matrigel with 25 mM CaCl{sub 2} as a crosslinker for alginate. In addition, 3D ReNcell VM culture exhibited self-renewal and differentiation on the microarray chip platform, which was efficiently monitored by enhanced green fluorescent protein (EGFP) expression of four NSC-specific biomarkers including sex determining region Y-box 2 (SOX2), glial fibrillary acidic protein (GFAP), synapsin1, and myelin basic protein (MBP) with the promoter-reporter assay system.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The suppression effect of dendritic cells maturation by adipose-derived stem cells through TGF-β1 related pathway

Our previous studies demonstrated that adipose-derived stem cells (ASCs) could modulate regulatory T cells (Treg) and prolong hind-limb allotransplant survival in vitro and in vivo. Dendritic cells (DCs) play a pivotal role in innate and adaptive immunity. The aim of this study is to investigate the underlying mechanism of ASCs in modulating DC maturation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Pax2 is essential for proliferation and osteogenic differentiation of mouse mesenchymal stem cells via Runx2

Highlights: • Knock-down of Pax2 inhibits the osteogenesis of mouse MSCs in vitro and in vivo. • Pax2 promotes the proliferation of mouse MSCs. • Pax2 enhances transcriptional activity of Runx2 and activates MAPK pathways. • Pax2 promotes the osteogenesis of mouse MSCs and may serve as a target for future clinical treatment. Mesenchymal stem cells (MSCs) have been widely studied in the field of regenerative medicine with the potential to solve osteoporosis. Paired box 2 (Pax2), as a transcription factor, is the master regulator of embryogenesis and oncogenesis. However, the function of Pax2 in osteogenesis is unknown. Here, we reported for the first time that the expression of Pax2 gradually increased during osteogenic differentiation of mouse MSCs, and osteoprogenitor cells. However, detected in osteoblastic cells of mouse tibia, the expression of Pax2 in the embryonic stage was higher than that in adulthood. In C3H/10/T1/2 cells and compact bone-derived mouse MSCs (mMSCs), Pax2 knock-down inhibited the proliferation of these cells, down-regulated the expression of osteogenic marker genes, as well as repressed the ALP activity and mineralization. In addition, Pax2 enhanced the transcriptional activity of Runx2, and activated the MAPK pathway genes (ERK, JNK and p38). Furthermore, knock-down of Pax2 repressed the mMSCs-mediated bone regeneration in an ectopic bone formation model. In conclusion, Pax2 promotes osteogenesis of mouse MSCs, suggesting that Pax2 has a role in the pathophysiology of bone related diseases, and has potential application in bone tissue regeneration.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Exosomes secreted from mesenchymal stem cells mediate the regeneration of endothelial cells treated with rapamycin by delivering pro-angiogenic microRNAs

Highlights: • MSC-derived exosomes play an important role in promoting endothelial regeneration treated with rapamycin in vitro. • A distinct class of exosomal miRNAs is identified to be tightly related to endothelial regeneration. • The therapeutic effects of MSC-exosomes may be ascribed to the delivery of pro-angiogenic miRNAs to endothelial cells. • MSC-exosomes may serve as a cell-free therapy for clinical treatment of delayed endothelial healing after DES implantation. Delayed endothelial healing after drug eluting stent (DES) implantation is a critical clinical problem in treatment of coronary artery diseases. Exosomes exhibit proangiogenic potential in a variety of ischemic diseases. However, the association of exosomes with endothelial regeneration after DES implantation has been rarely reported. In this study, we aimed to investigate the therapeutic effects of mesenchymal stem cell (MSC)-derived exosomes on endothelial cells treated with rapamycin and explore the potential mechanisms of MSC-derived exosomes in promoting endothelial regeneration. Exosomes were isolated from MSCs by ultracentrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis, and Western blot assay. The in vitro effects of MSC-derived exosomes on the proliferation and migration of endothelial cells treated with rapamycin were evaluated by integrated experiment, cell counting kit-8, scratch, tube formation, and transwell assays. And the apoptosis of rapamycin-induced endothelial cells loaded with MSC-derived exosomes was detected using TUNEL and Annexin-V FITC and PI double-staining assays. The microRNA (miRNA) cargo of MSC-derived exosomes was identified by high-throughput RNA sequencing. Pro-angiogenic miRNAs and key pathways were further characterized. Our results indicated that MSC-derived exosomes could be ingested into umbilical vein endothelial cells (HUVECs) and significantly enhanced cell proliferation rate, migratory and tube-forming capabilities in vitro. MSC-derived exosomes also inhibited the apoptosis of HUVECs induced by rapamycin. A distinct class of exosomal miRNAs was further identified, including six miRNAs tightly related to neovasculogenesis. Silencing the expression of exosomal miRNA-21–5p and let-7c-5p attenuated the pro-proliferative and pro-migratory capacity of MSC-derived exosomes. Moreover, functional enrichment analysis indicated that metabolic pathways might contribute to reendothelialization. This study highlights a proregenerative effect of MSC-derived exosomes in vitro, which may be partly explained by the delivery of pro-angiogenic miRNAs to endothelial cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Kindlin-3 mutation in mesenchymal stem cells results in enhanced chondrogenesis

Identifying patient mutations driving skeletal development disorders has driven our understanding of bone development. Integrin adhesion deficiency disease is caused by a Kindlin-3 (fermitin family member 3) mutation, and its inactivation results in bleeding disorders and osteopenia. In this study, we uncover a role for Kindlin-3 in the differentiation of bone marrow mesenchymal stem cells (BMSCs) down the chondrogenic lineage. Kindlin-3 expression increased with chondrogenic differentiation, similar to RUNX2. BMSCs isolated from a Kindlin-3 deficient patient expressed chondrocyte markers, including SOX9, under basal conditions, which were further enhanced with chondrogenic differentiation. Rescue of integrin activation by a constitutively activated β{sub 3} integrin construct increased adhesion to multiple extracellular matrices and reduced SOX9 expression to basal levels. Growth plates from mice expressing a mutated Kindlin-3 with the integrin binding site ablated demonstrated alterations in chondrocyte maturation similar to that seen with the human Kindlin-3 deficient BMSCs. These findings suggest that Kindlin-3 expression mirrors RUNX2 during chondrogenesis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Nrf2 activation is involved in osteogenic differentiation of periodontal ligament stem cells under cyclic mechanical stretch

Highlights: • Cyclic mechanical stretch increases the nuclear accumulation of Nrf2 in PDLSCs. • T-BHQ promotes osteogenic differentiation under cyclic mechanical stretch. • Nrf2 activation may improve alveolar bone remodeling during orthodontic treatment. During orthodontic treatment, mechanical stretch serves a crucial function in osteogenic differentiation of periodontal ligament stem cells (PDLSCs). Up-regulated reactive oxygen species (ROS) level is a result of cyclic mechanical stretch in many cell types. Nuclear factor erythroid-2-related factor-2 (Nrf2) is a master regulator in various antioxidants expression. However, it is not known whether cyclic mechanical stretch could induce the ROS generation in PDLSCs and whether Nrf2 participated in this process. The present study was aimed to investigate the role of Nrf2 in PDLSCs under cyclic mechanical stretch. Our results showed that cyclic mechanical stretch increased ROS level and the nuclear accumulation of Nrf2 during osteoblast differentiation. Knocking down Nrf2 by siRNA transfection increased ROS formation and suppressed osteogenic differentiation in PDLSCs. T-BHQ, a Nrf2 activator, promoted the osteogenic differentiation in PDLSCs under cyclic mechanical stretch, and improved the microstructure of alveolar bone during orthodontic tooth movement in rats by employing micro-CT system. Taken together, Nrf2 activation was involved in osteogenic differentiation under cyclic mechanical stretch in PDLSCs. T-BHQ could promote the osteogenic differentiation in vitro and in vivo, suggesting a promising option for the remodeling of the alveolar bone during orthodontic tooth movement.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Defining optimal enzyme and matrix combination for replating of human induced pluripotent stem cell-derived cardiomyocytes at different levels of maturity

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) create an unlimited cell source for basic and translational research. Depending on the maturity of cardiac cultures and the intended applications, obtaining hiPSC-CMs as a single-cell, monolayer or three-dimensional clusters can be challenging. Here, we defined strategies to replate hiPSC-CMs on early days (D15-30) or later more mature (D60-150) differentiation cultures. After generation of hiPSCs and derivation of cardiomyocytes, four dissociation reagents Collagenase A/B, Collagenase II, TrypLE, EDTA and five different extracellular matrix materials Laminin, iMatrix-511, Fibronectin, Matrigel, and Geltrex were comparatively evaluated by imaging, cell viability, and contraction analysis. For early cardiac differentiation cultures mimicking mostly the embryonic stage, the highest adhesion, cell viability, and beating frequencies were achieved by treatment with the TrypLE enzyme. Video-based contraction analysis demonstrated higher beating rates after replating compared to before treatment. For later differentiation days of more mature cardiac cultures, dissociation with EDTA and replating cells on Geltrex or Laminin-derivatives yielded better recovery. Cardiac clusters at various sizes were detected in several groups treated with collagenases. Collectively, our findings revealed the selection criteria of the dissociation approach and coating matrix for replating iPSC-CMs based on the maturity and the requirements of further downstream applications.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Extracellular IL-37 promotes osteogenic and odontogenic differentiation of human dental pulp stem cells via autophagy

The osteogenic and odontogenic differentiation of dental pulp stem cells (DPSCs) contribute to restoration and regeneration of dental tissue. Previous study indicated that interleukin-37 (IL-37) was an anti-inflammatory factor that affected other pro-inflammatory signals. The aim of this study was to explore the effects of IL-37 on the differentiation of DPSCs. DPSCs were cultured in growth medium with different concentrations of IL-37. We selected the optimal concentration for the following experiments by alkaline phosphatase (ALP) activity analysis, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot. Cell counting kit assay (CCK-8) and 5-Ethynyl-2-Deoxyuridine (EdU) assay were conducted to assess the effects of IL-37 on the proliferation of DPSCs. ALP activity assay and staining, alizarin red S (ARS) staining, qRT‐PCR, Western blot as well as immunofluorescence staining were conducted to assess differentiation ability of DPSCs. Western blot, immunofluorescence staining and transmission electron microscopy (TEM) were utilized to examine cell autophagy. Results showed that IL-37 enhanced the osteogenic and odontogenic differentiation ability of DPSCs with no significant influence on the proliferation of DPSCs. Autophagy in DPSCs was activated by IL-37. Activation of autophagy enhanced osteogenesis and odontogenesis of DPSCs, whereas inhibition of autophagy suppressed DPSCs osteogenic and odontogenic differentiation. In conclusion, IL-37 increased osteogenic and odontogenic differentiation via autophagy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Galectin-1 secreted by bone marrow-derived mesenchymal stem cells mediates anti-inflammatory responses in acute airway disease

The hallmarks of allergic airway disease (AAD) include infiltration of inflammatory cells into the bronchoalveolar space. Bone marrow derived mesenchymal stem cells (BMSCs) show anti-inflammatory properties in AAD. In addition, galectin-1 (Gal-1) is a lectin significantly upregulated upon inflammation and is also known to mediate potential anti-inflammatory responses. We hypothesized that BMSCs regulated inflammatory responses by secretion of Gal-1 during AAD pathogenesis. BMSCs were isolated from murine femurs and tibiae and adoptively transferred into an ovalbumin-induced AAD mouse model. Knockdown of Gal-1 in BMSCs was performed using shRNA. Flow cytometry, ELISAs, and immunohistology were performed to analyze inflammatory responses in mice, and a Transwell system was used to establish an in vitro co-culture system of lung epithelial cells (MLE-12) and BMSCs. Administration of BMSCs significantly upregulated Gal-1 expression upon inflammation and decreased infiltration of inflammatory cells and secretion of proinflammatory cytokines in vivo. In addition, we showed that this function was mediated by reduced activation of the MAPK p38 signaling pathway. Similar observations were found using an in vitro lipopolysaccharide-induced model when MLE-12 cells were co-cultured with BMSCs. Gal-1 secretion by BMSCs alleviated inflammatory responses observed in AAD and hence provides a promising therapeutic alternative to AAD patients insensitive to conventional drug treatments.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Protective effects of intravitreal administration of mesenchymal stem cell-derived exosomes in an experimental model of optic nerve injury

Traumatic optic neuropathy results in the loss of retinal ganglion cells (RGCs), leading to unavoidable visual impairment. However, there is no effective therapy by far. Accumulated studies support the perception that mesenchymal stem cells (MSCs) secrete exosomes that serve as a protective paracrine factor. The study aimed to explore and evaluate the potential therapeutic effects of intravitreal transplantation of MSC-derived exosomes (MSC-exos) in an experimental model of optic nerve crush (ONC). Exosomes were isolated from rat MSCs and characterized by transmission electron microscope and western blotting. At the onset of ONC, a single intravitreal injection of exosomes or PBS was administered to the rats. At day 30, hematoxylin and eosin staining, immunohistochemistry, and βIII-tubulin staining were performed to evaluate the survival of RGCs. Moreover, TUNEL assay was used to examine the apoptosis of RGCs. Inflammation-relevant factors were identified via quantitative polymerase chain reaction. The expression levels of cell apoptosis-related molecules and key members of the PI3K/AKT signaling pathway were determined via western blot analysis. We found that MSC-exos exhibited typical characteristic morphologies (cup-shaped) and sizes (peak size of 93 nm). Furthermore, they exhibited substantial expression of the exosome markers CD63 and TSG101, but lacked the expression of the cellular marker GM130. Treatment with intravitreal MSC-exos notably promoted the survival of RGCs in ONC rats. The level of pro-inflammatory cytokines, including TNF-α, IL-1β, IL-6, IL-8, and MCP-1, were reduced, whereas those of the anti-inflammatory factor IL-10 were increased. Moreover, the apoptosis induced by ONC was decreased by the administration of MSC-exos via upregulation of the Bcl-2/Bax ratio and downregulation of caspase-3 activity. Furthermore, MSC-exos significantly stimulated AKT phosphorylation, whereas LY294002 restored the apoptosis-preventing effects of MSC-exos. The results of our results demonstrated that intravitreal administration of MSC-exos ameliorates ONC-induced injury in a rat model. These findings might aid in the development of effective exosome-based therapeutic strategies for the treatment of optic nerve degeneration.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Selenomethionine protects oxidative-stress-damaged bone-marrow-derived mesenchymal stem cells via an antioxidant effect and the PTEN/PI3K/AKT pathway

Highlights: • Oxidative stress stimuli by H{sub 2}O{sub 2} suppressed osteogenic differentiation of BMSCs. • Selenomethionine could alleviate osteogenic dysfunction of oxidative-stress-damaged BMSCs. • Selenomethionine rescued osteogenic ability partly through the modulation of the PTEN/PI3K/AKT pathway. Dental implant surgery is currently a routine therapy for the repair of missing dentition or dentition defects. Both clinical and basic research have elucidated that oxidative stress caused by the accumulation of reactive oxygen species (ROS) for various reasons impairs the process of osteointegration after dental implantation. Therefore, the osteogenic micro-environment must be ameliorated to decrease the damage caused by oxidative stress. Selenomethionine (SEMET) has been reported to play an important role in alleviating oxidative stress and accelerating cell viability and growth. However, it remains unclear whether it exerts protective effects on bone-marrow-derived mesenchymal stem cells (BMSCs) under oxidative stress. In this study, we explored the influence of selenomethionine on the viability and osteogenic differentiation of BMSCs under oxidative stress and the underlying mechanisms. Results showed that 1 μM selenomethionine was the optimum concentration for BMSCs under H{sub 2}O{sub 2} stimulation. H{sub 2}O{sub 2}-induced oxidative stress suppressed the viability and osteogenic differentiation of BMSCs, manifested by the increases in ROS production and cell apoptosis rates, and by the decrease of osteogenic differentiation-related markers. Notably, the aforementioned oxidative damage and osteogenic dysfunction induced by H{sub 2}O{sub 2} were rescued by selenomethionine. Furthermore, we found that the PTEN expression level was suppressed and its downstream PI3K/AKT pathway was activated by selenomethionine. However, when PTEN was stimulated, the PI3K/AKT pathway was down-regulated, and the protective effects of selenomethionine on BMSC osteogenic differentiation diminished, while the inhibition of PTEN up-regulated the protective effects of selenomethionine. Together, these results revealed that selenomethionine could attenuate H{sub 2}O{sub 2}-induced BMSC dysfunction through an antioxidant effect, modulated via the PTEN/PI3K/AKT pathway, suggesting that selenomethionine is a promising antioxidant candidate for reducing oxidative stress during the process of dental implant osteointegration.

60 APPLIED LIFE SCIENCES↗