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©The Author(s) 2024.
World J Stem Cells. Jun 26, 2024; 16(6): 623-640
Published online Jun 26, 2024. doi: 10.4252/wjsc.v16.i6.623
Published online Jun 26, 2024. doi: 10.4252/wjsc.v16.i6.623
Table 1 Typical pre-clinical and clinical studies involving mesenchymal stem cells primed using different strategies
| Ref. | Model type | Cell source and pre-treatment | Main findings |
| Pre-treatment of MSCs by physical manipulation | |||
| Kim et al[17], 2009 | In vitro studies | BM-MSCs pre-treated with IP (with two cycles of 30 min anoxia/reoxygenation) | IP significantly reduced apoptosis in MSCs through activation of Akt [Ser(473)] and ERK1/2 [Thr(202)/Tyr(204)] and nuclear translocation of HIF-α. There was simultaneous induction of miR-210 in the IP MSCs. RT-PCR array for rat apoptotic genes, computational target gene analyses, and luciferase reporter assay identified FLICE-associated huge protein/caspase-8-associated protein-2 in (PC)MSCs as the target gene of miR-210, responsible for improved cell survival |
| Fang et al[24], 2019 | In vitro study | Stretch pre-treatment of AD-MSCs | Human ADSCs were subjected to cyclic stretch stimulation, significantly promoting their proliferation, adhesion, and migration. It also reduced cellular apoptosis but inhibited adipogenesis and increased osteogenesis. Long-term stretch promotes cell aging but without any size or morphological changes. Stretching also caused the induction of PI3K/AKT and MAPK pathways |
| Bianconi et al[28], 2023 | A femur defect rat model | ElecS in 2D and 3D cultures | A femur defect rat model was used to assess the healing effects of MSCs pre-treated by ElecS in 2D and 3D cultures for one hour/day for seven days. The bone healing effect was evaluated at one, four-, and eight weeks post-surgery. In all groups, the percentage of new bone increased, while fibrous tissue and CD68+ cell count were reduced. However, these and other healing features, like mineral density, bending stiffness, the amount of new bone and cartilage, and the gene expression of osteogenic markers, did not significantly differ between groups |
| Li et al[29], 2023 | In vitro study | UC-MSCs pre-exposed to (2% O2) hypoxia + treatment with IL-1β, TNF-α, INF-γ for 24 h | Combined pretreatment with hypoxia and inflammatory factors changed UC-MSC morphology without changing viability, proliferation, or size. Also, pretreatment did not alter surface marker expression or mitochondrial function and integrity. However, pretreatment promoted UC-MSC apoptosis and senescence. Interestingly, immune regulation-related genes and protein expression significantly increased. These molecular changes increased peripheral blood mononuclear cell and NK cell proliferation and reduced NK cell-induced toxicity |
| Liu et al[30], 2021 | Mice model of ICH-induced brain injury using collagenase IV | Hypoxic OM-MSCs treated with hypoxia (3% O2) for 48 h | This study investigated the neuroprotective effects of hypoxia-preconditioned OM-MSCs in treating ICH in mice. Hypoxia-pretreated OM-MSCs reduced microglial activation and IL-1β and TNF-α. Also, there was a significant reduction in pyroptosis and pyroptosis-associated proteins in peri-hematoma brain tissues. Molecular studies showed reduced microglial NLRP3 expression, caspase-1, and reduced membrane pores on microglia after ICH |
| Dong et al[31], 2021 | In vitro study | Macrophages co-cultured with BM-derived MSCs with mechanical stretch | Macrophages co-cultured with MSCs with mechanical stretch efficiently induced osteogenic differentiation of MSCs. Cyclical stretch caused macrophages to be polarized to the anti-inflammatory M2 phenotype, inducing IL-10 and TGF-β expression. YAP activation and nuclear translocation also caused BMP2 expression to facilitate MSC osteogenesis |
| Romanek et al[32], 2018 | In vitro study | Porcine MSCs under HHP of 20, 30, 40, 50, or 60 MPa (1 h at 24 °C) | Porcine BM-MSCs were cultured in vitro and, before cryopreservation, subjected to HHP, i.e., 20, 30, 40, 50, or 60 MPa for 1 h at 24 °C. Immediately after thawing and on day 8, the cells were assessed for survival and proliferation. MSCs subjected to 40, 50, and 60 MPa showed improved survival vs the control, while cells exposed to 40 MPa HHP had higher proliferation than the control group after eight days of culture |
| Hu et al[33], 2016 | In vitro and in vivo study | Cynomolgus monkey MSCs were exposed to 0.5% oxygen for 24 h | MSCs were exposed to 0.5% oxygen (HP-MSCs) for 24 h and later used to treat MI in cynomolgus monkeys. Hypoxia pretreatment increased the expression of pro-survival/pro-angiogenic factors in vitro. Post-transplantation, they reduced the infarct size and LVEF on day 90 after treatment compared to the control group. This was also accompanied by higher cardiomyocyte proliferation, blood vessel density, myocardial glucose uptake, and engraftment of the transplanted cells. There were no arrhythmogenic changes |
| Sun et al[34], 2016 | In vitro study | BM-derived MSCs and ligament tissue-derived fibroblast under the uniflex/bioflex culture system | The cells were uniaxially or radially stretched under 5%, 10%, and 15% strains at 0.1, 0.5, and 1.0 Hz. Exposure to uniaxial stretch (15% at 0.5 Hz; 10% at 1.0 Hz) increased proliferation and collagen production in fibroblast. On the other hand, the uniaxial strains (5%, 10%, and 15%) at 0.5 Hz and 10% strain at 1.0 Hz were favorable for MSCs. Radial strain did not affect fibroblast, but radial strains 5%, 10%, and 15% at 0.1 Hz increase MSC proliferation. The data supported the differential response of the cells depending on cell type under different types of mechanical stress |
| Wang et al[35], 2013 | In vitro study | Cyclical compressive stress on rat BM-derived MSCs | Dynamic cyclical compressive stress remarkably increased MSCs quantity and viability during early chondrogenesis, increasing cyclin D1, CDK4, and Col2α1. MEK/ERK and p38 MAPK were not activated, but BMP signaling was activated in mechanotransduction for chondrogenic proliferation |
| Pre-treatment with chemicals and pharmacological agents | |||
| Qazi et al[36], 2022 | Rat model of MI | 3D-cultured rat BM-MSCs and treated with zebularine | MSCs were cultured on a collagen scaffold and, after treatment with zebularine for cardiac differentiation, were used to treat the rat MI model. Compared to the MI control, there was a significant improvement in cardiac function in the zebularine-treated scaffold-cultured group. A significant reduction in a fibrotic scar and an improvement in LV wall thickness preserved LV remodeling. Blood vessel density in and around the infarct area was also improved |
| Aslam et al[37], 2020 | In vitro studies | UC-MSCs pre-treated with IH | The scratch assay showed a decreased scratch area in the case of IH-treated MSCs at 24 h, extending to complete closure of the scratch area at 48 h. Histological analysis showed reduced inflammation and completely remodeled epidermis and dermis without scar formation. There was a time-dependent reduction in IL-1β and IL-6. There was a simultaneous increase in Bcl-2 and TGF-β, VEGF, Bcl-2, and MMP-9, with increased angiogenesis and reduced inflammation and apoptosis |
| Li et al[38], 2015 | Rat model of AMI | Atorvastatin-treated rat BM-MSCs | Atorvastatin pretreatment induced CXCR4 expression in MSCs and supported their emigrational potential. When delivered intravenously in a rat model of AMI, the cells homed into the infarcted myocardium, participated in myocardial repair, and preserved global cardiac function |
| Liu et al[39], 2014 | Rat model of AMI | HIF-α prolyl hydroxylase inhibitor DMOG | DMOG pre-treatment of BM-MSCs significantly enhanced the expression of pro-survival and pro-angiogenic factors, including HIF-1α, VEGF, glucose transporter 1, and phospho-Akt. DMOG-treated MSCs also survived better than naïve MSCs post-engraftment in the rat model of AMI, in addition to increasing blood vessel density in and around the infarcted myocardium |
| Shinmura et al[40], 2011 | Nude rat model of AMI | Pioglitazone pre-treated human MSCs | MSCs pretreated with pioglitazone were injected two weeks after MI. Pretreatment with pioglitazone significantly improved change in LVFS. Immunohistochemistry showed increased cardiomyogenic transdifferentiation of the transplanted cells and improved global cardiac function |
| Suzuki et al[41], 2010 | In vitro studies | Diazoxide pre-treated BM-MSCs | Treatment of MSCs with DZ (200 μM) induced NF-κB-dependent miR-146a expression to support cell survival. Abrogation of miR-146a expression using an antisense miR-146a inhibitor abolished DZ-induced cytoprotective effects. The computational analysis demonstrated a consensus putative target site of miR-146a in the 3’ untranslated region of Fas mRNA regulating cell apoptosis. A Luciferase reporter assay revealed forced expression of miR-146a downregulated Fas expression |
| Pre-treatment of MSCs with cytokines and growth factors | |||
| Chen et al[42], 2023 | In vitro studies | hUC-MSCs pre-treated with IFN-γ & TNF-α alone or combined in a colitis mice model | Treatment with IFN-γ alone increased PD-L1 in hUC-MSCs, while TNF-α alone did not. Co-treatment with IFN-γ and TNF-α increased PD-L1 expression. IFN-γ also activated the JAK/STAT1 signaling pathway, increased the IRF1 transcription factor, promoted the binding of IRF1 and the PD-L1 gene promoter, and finally increased PD-L1 mRNA. TNF-α significantly enhanced IFN-γ-induced JAK/STAT1/IRF1 activation. TNF-α increased IFN-γ receptors via the NF-κB signaling pathway, significantly enhancing IFN-γ signaling. Finally, co-treatment inhibited lymphocyte proliferation, reduced mucosal damage, inflammatory cell infiltration, and up-regulation of inflammatory factors in colitis mice |
| Chen et al[43], 2023 | In vitro studies | Rat BM-MSCs treated with SDF-1α | CXCR4 expression was observed on BM-MSCs by immunofluorescence staining. Treatment with SDF-1α increased collagen X and MMP13 expression during cartilage differentiation but with no change in collagen II or aggrecan. SDF-1α treated MSCs were validated in primary chondrocytes. SDF-1α increased p-GSK3β and β-catenin in MSCs. Abrogation of this pathway using ICG-001 (5 μmol/L) abrogated the SDF-1α-mediated up-regulation of collagen X and MMP13 expression in MSCs |
| Esmaeili et al[44], 2021 | Rat model of AMI | Rat BM-MSCs overexpressing VEGF and pre-treated with SDF-1α | SDF-1α pre-treatment significantly reduced LDH release in MSCs, significantly thus increasing their survival more than the naïve control MSCs. The LVEF was improved considerably with a concomitant reduction in the infarct size in the animals in SDF-1α pretreated cells compared to the other treatment groups of animals |
| Lu et al[45], 2009 | In vitro studies and Rat model of AMI | BM-derived Sca-1+ cells exposed to OGD and pre-treatment with IGF-1 | Exposure to OGD for up to 12 h activated Erk1/2 in Sca-1(+) cells. Moreover, higher intracellular calcium with simultaneous PKC activation was also observed. Pretreatment with nifedipine or dantrolene reduced cellular calcium, abrogated PKC, and Erk1/2 activation. Pretreatment with 100 nM IGF-1 increased cell resistance to ischemia via Erk1/2 activation to improve their survival under OGD and post-engraftment of the infarcted heart |
| Hahn et al[46], 2008 | Rat model of AMI | Rat BM-MSCs pre-treated with FGF-2 and IGF-1 | Pre-treatment of MSCs with bFGF + IGF1 increased the expression of cardiac transcription factors and survival. Transplantation of the pre-treated cells in a rat myocardial infarction model reduced infarct size and improved global cardiac function compared to untreated MSCs. Pre-treatment with growth factors enhanced gap junction formation in the transplanted MSCs without any arrhythmias |
| Pre-treatment of MSCs by genetic manipulation | |||
| Li et al[47], 2018 | Isoproterenol-induced heart failure model in rats | MSCs overexpressing ADM | Transplantation of ADM-MSCs significantly improved heart function and reduced the size of the fibrotic area. Fluorescence microscopy revealed that ADM-MSCs survived considerably better in the heart. ADM-MSC treatment also improved heart function through enhanced antifibrotic activity |
| Gómez-Mauricio et al[48], 2016 | Porcine heart model of MI | Porcine adipose tissue-derived MSCs genetically modified for HGF-1 and IGF-1 | I/M delivery of MSCs with IGF-1 and HGF-1 was safe. Inflammation was significantly reduced in some myocardial sections analyzed. There was a significant increase in blood vessel density in ischemic tissue. Although cardiac function parameters were not significantly improved, cell retention and IGF-1 overexpression were confirmed within the myocardium. Concomitant IGF-1- and HGF overexpression promoted a synergistic effect |
| Gnecchi et al[49], 2009 | Rat model of acute MI | MSCs overexpressing Akt1 | Akt-MSCs, or PBS, were used to treat rats with experimental MI. High energy metabolism and basal 2-DG uptake were evaluated on isolated hearts using phosphorus-31 NMR 72 h and two weeks after MI. Treatment with Akt-MSCs increased 2-DG uptake in the residual intact myocardium vs PBS or the naïve MSC treatment. Also, Akt-MSC-treated hearts had normal pH and functional recovery after MI, thus showing that Akt-MSCs preserved normal metabolism and pH in the surviving myocardium |
| Haider et al[50], 2008 | Rat model of acute MI | Rat BM-MSCs overexpressing IGF-1 | Overexpression of IGF-1 led to enhanced phosphoinositide 3-kinase, Akt, and Bcl-xL and inhibition of glycogen synthase kinase 3beta besides the release of SDF-1α in BM-MSCs. Intramyocardially transplantation of IGF-expressing MSCs of the transplanted MSCs with massive mobilization and homing of ckit(+), MDR1(+), CD31(+), and CD34(+) cells into the infarcted heart. Infarction size was significantly reduced vs control. There was extensive angiomyogenesis in the infarcted heart and improved LVEF |
| Pre-treatment of stem cells in clinical trials | |||
| Bartunek et al[51], 2013 | C-CURE Clinicaltrial.gov ID: NCT00810238 | hBM-MSCs pre-treated with a cocktail of bioactive molecules | In 100% of cases, treatment using MSCs pre-treated with a cardiopoietic cocktail was without complications. Cardiopoietic cell therapy did not induce systemic toxicity. LVEF was significantly improved compared to the standard therapy without cell treatment. Cell therapy also increased the 6-min walk distance, improving the New York Heart Association functional class, quality of life, and physical performance |
| Bartunek et al[52], 2016 | CHART-1 Clinicaltrial.gov ID: NCT01768702 | Cardiopoietic MSCs C3BS-CQR-1 | Patients (n = 351) with symptomatic advanced HF with reduced LVEF (< 35%) were randomized to receive C3BS-CQR-1 or a sham procedure. Treatment with C3BS-CQR-1 resulted in a significant progressive reduction in LVEDV and LVESV during a 52-wk follow-up. Interestingly, the most considerable reverse remodeling was observed in the patients receiving moderate injections (< 20) |
| Qayyum et al[53], 2017 | MyStromalCell trial. ClinicalTrials.gov ID: NCT01449032 | VEGF-A165-stimulated adipose-derived stromal cells ASCs | The MyStromalCell trial is a randomized, double-blind, placebo-controlled study in sixty patients with refractory angina, CCS/NYHA class II-III, LVEF > 40%, and at least one significant coronary artery stenosis. ASCs were culture-expanded and primed with VEGF-A165. Six months of follow-up showed that the treatment was safe and improved exercise tolerance compared to placebo |
Table 2 Typical examples of growth factors, bioactive molecules, chemicals, and pharmacological agents used to pre-treat mesenchymal stem cells
| GF, cytokines, & other bioactive molecules | Transgenes for genetic modulation of MSCs | Chemicals and pharmacological agents |
| Adrenomedullin | Adrenomedullin | Cobalt chloride |
| Angiopoietin-1 | Akt | 2,4-dinitrophenol |
| Angiotensin-II | Akt + angiopoietin | Aliskiren |
| Basic fibroblast GF | Bcl2 | Atorvastatin |
| Epidermal GF | CXCR4, CXCR7 | Diazoxide |
| GCSF | GATA4 | Deferoxamine |
| Hepatocyte GF-1 | Focal adhesion kinase | Dimethyloxalylglycine |
| Insulin-like GF-1 | Hepatocyte GF-1 | Glucagon-like protein-1 |
| Interferon-γ | Hypoxia-inducible factor | Hydrogen peroxide |
| Interleukin1-β | Insulin-like GF-1 | Lipopolysaccharide |
| Interleukin 6 | Integrin subunit-alpha4 | Nicorandil |
| Melatonin | Kallikerin-1 | Pioglitazone |
| Oxytocin | cMyc | Salvianolic acid |
| Platelet-derived GF | Oct4 | Simvastatin |
| Stromal cell-derived factor 1α | Protein kinase C | Sevoflurane |
| Thymosin β4 | Sox2 | Sodium butyrate |
| Transforming GF-β | Stromal cell-derived factor 1α | Tadalafil |
| Tumor necrosis factor-α | Tumor necrosis factor-α receptor | Trimetazidine |
| Vascular endothelial GF | Vascular endothelial GF | Trace elements like Zn |
| Vitamin E | Various microRNAs | Valproic acid |
Table 3 Studies for further reading on physical manipulation and genetic priming strategies
| Ref. | Model type | Cell source and pre-treatment | Main findings | |
| Pre-treatment of MSCs by physical manipulation | ||||
| Izadpanah et al[103], 2022 | In vitro | 5-Aza treatment + static and microfluidic cell culture systems | 5-Aza induced cardiac-specific markers in MSCs, but this induction was significantly increased after exposure to both 5-Aza and shear stress, showing their synergistic effects vs 5-Aza or in shear stress-only groups. These results demonstrated that MSCs’ exposure to 5-Aza and shear stress is required for high-level cardiac gene expression | |
| Manjua et al[104], 2021 | In vitro/in vivo models for angiogenesis | MSCs exposed to magnetic pre-treatment | MSCs cultured on polyvinylalcohol and gelatin-based scaffolds containing iron oxide nanoparticles were exposed to a magnetic field. The cells showed significantly increased VEGF-A production and altered their morphology and alignment. MSCs’ angiogenic potential was observed by the increase in angiogenic response using conditioned media in vitro and in vivo | |
| Helms et al[105], 2020 | In vitro | AD-SCs pre-treated with TSB or mechanical stimulation or their combined action | The study was intended to show if mechanical stimulation can support or replace TSB-induced differentiation of Ad-SCs. ASC or pre-differentiated SMC exposed to pulsatile perfusion for ten days with or without TSB resulted in collagen-I expression and circumferential orientation of the cells around the lumen. Molecular studies showed upregulation of αSMA and calponin expression. On the other hand, contractility and smoothelin expression required both mechanical and TSB stimulation | |
| Vaez et al[106], 2018 | BM-MSCs in static 2D and microfluidic cell culture systems | There was a clear but insignificant difference between the beating rate of APCs and CNCs in both 2D and the microfluidic system during 30 d. Data from RT-PCR showed GATA4, Nkx2.5, CX43, cTnI, cTnT, and β-MHC induction during four weeks more in microfluidic chips than those co-cultured in 24-well plates. Combined shear stress and co-culture with cardiomyocytes significantly enhanced the differentiation rate vs co-culture alone | ||
| Popa et al[107], 2016 | In vitro | hAD-SCs pre-treated by MNPs integrated in κC hydrogels | The MNP concentration in the κC hydrogels significantly influenced the cell viability, cell content, and metabolic activity. The optimal MNP concentration was 5% in κC. Exposure to magnetic actuation further altered their gene expression profile, favoring chondrogenic phenotype induction | |
| Shi et al[108], 2011 | In vitro | MSCs’ exposure to CCMT | RhoA activity after CCMT stimulation was reduced. Pre-treatment of CCMT-stimulated MSCs with LPA, a RhoA activator, recovered ALP activity and Runx2 expression. In contrast, pre-treatment with C3 toxin, a RhoA inhibitor, reduced ALP activity with a concomitant reduction in Runx2. These results showed inhibition of Runx2 expression after the RhoA-ERK1/2 pathway mediates CCMT stimulation | |
| Liu et al[109], 2011 | hMSCs under perfusion culture system to produce FSS | hMSCs subjected to a perfusion culture system to produce FSS, which activated ERK1/2. The pre-treatment enhanced the pro-osteogenic gene expression profile in the cells via activating NF-κB and BMP. FSS inducing the osteogenic differentiation of hMSCs will provide new targets for osteoporosis and related bone-wasting diseases | ||
| Kasten et al[110], 2010 | In vitro | BM-MSCs subjected integrin integrin-induced and inhomogeneous magnetic force exposure | Exposure to inhomogeneous magnetic forces increased Sox 9 (a marker of chondrogenesis) and decreased ALP expression. Molecular studies showed that VEGF induction induced by physical forces involved Akt activation. The results showed that the biological functions of MSCs can be stimulated by pretreatment with integrin-mediated mechanical forces and inhomogeneous magnetic field exposure | |
| Pre-treatment of MSCs by genetic manipulation | ||||
| Li et al[111], 2023 | In vitro and mice model of PD | hMSCs overexpressing VEGF189 | hMSC overexpressing VEGF189-GFP significantly increased VEGF expression and slightly increased viability of the cells vs naïve cells. Transplantation of VEGF expressing MSCs significantly improved mechanical allodynia and inhibited the site’s TRPV1 expression. TRPV1 agonists could partially block such pain relief effects. There was no tumorigenicity or neuron degeneration in hMSCs expressing VEGF189-GFP | |
| Yu et al[112], 2023 | In vitro and in vivo mice model of alkali-burned cornea | AD-MSCs overexpressing IGF-1 | Treatment with MSCs overexpressing IGF-1 significantly recovered corneal morphology and function vs control and IGF-1 protein eyedrops. The healing of corneal epithelium and limbus, the inhibition of corneal stromal fibrosis, angiogenesis, and lymphangiogenesis, and the repair of corneal nerves were observed. In vitro experiments showed that MSCs with IGF-1 promoted trigeminal ganglion cell activity and maintained limbal stem cells’ stemness | |
| Singh et al[113], 2018 | In vitro | Pharmacological and genetic manipulation of MSCs to enhance survivin | Induction of survivin is essential for MSC survival, expansion, lineage commitment, and migrational potential. On the other hand, pharmacological or genetic blockade of survivin expression in mouse and human BM-MSC increased caspase 3 and 7 expression and reduced proliferation, resulting in fewer MSC and clonogenic colony-forming unit-fibroblasts, growth factor (i.e., b-FGF or PDGF)-mediated survivin modulation represents a novel therapeutic strategy | |
| Konoplyannikov et al[114], 2013 | In vitro and in vivo in rat model of MI | Simultaneous overexpression of IGF-1, VEGF, sSDF-1a, HGF-1 in SKM | Overexpression of four growth factors led to the induction of multiple angiogenic and pro-survival factors, including secreted frizzled-related protein-1,2,4,5, matrix metalloproteinases-3 and 9, connexin-43, netrin-1, Nos-2, Wnt-3, Akt, MAPK42/44, Stat3, NFκB, HIF-1α, and protein kinase C. Transplantation of the genetically modified cells causes extensive neomyogenesis and angiogenesis in the infarcted heart, attenuating infarct size and improving global heart function at eight weeks vs control animals. There was also massive mobilization and homing of stem/progenitor cells from the peripheral circulation, the bone marrow, and the heart for participation in infarcted myocardium repair | |
| Jiang et al[115], 2006 | In vitro and in vivo study in rat model of MI | Rat BM-MSCs are co-overexpressing Ang-1 and Akt | MSCs co-overexpressing Ang-1 and Akt survived better under anoxia vs naïve MSCs. At two weeks after cell transplantation, MAAs survived significantly more than the naïve MSCs in the infarcted heart. The heart function indices were significantly improved LVEF and fractional shortening vs control | |
| Ye et al[116], 2005 | In vitro and in vivo using a rat model of acute MI | SKMs genetically modulated to overexpress VEGF | The genetically modified cells expressed copious amounts of VEGF. Transplantation of the cells into the infarcted heart significantly increased blood vessel density compared to control animals. LVEF and fractional shortening were improved considerably compared to control-treated animals, and regional flow improved | |
- Citation: Haider KH. Priming mesenchymal stem cells to develop “super stem cells”. World J Stem Cells 2024; 16(6): 623-640
- URL: https://www.wjgnet.com/1948-0210/full/v16/i6/623.htm
- DOI: https://dx.doi.org/10.4252/wjsc.v16.i6.623