Priming mesenchymal stem cells to develop “super stem cells”

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

5-Aza: 5-azacytidine; AD-MSC: Adipose tissue-derived mesenchymal stem cell; AD-SC: Adipose tissue-derived stem cell; ALP: Alkaline phosphatase; Ang-1: Angiopoietin-1; APC: Almost pure cardiomyocytes; ASC: Adipose tissue-derived stromal cell; b-FGF: Basic fibroblast growth factor; BM-MSC: Bone marrow derived-stem cells; BMP: Bone morphogenetic protein; CCMT: Cyclic mechanical tension; CNC: Cardiac niche cell; FSS: Fluid shear stress; GATA4: GATA-binding protein 4; hAD-SC: Human adipose tissue-derived stem cells; HGF-1: Hepatocyte growth factor-1; HIF: Hypoxia-inducible factor; hMSC: Human mesenchymal stem cells; IGF-1: Insulin-like growth factor-1; LPA: Lysophosphatidic acid; LVEF: Left ventricular ejection fraction; MAA: Mesenchymal stem cells co-overexpressing angiopoietin-1 and Akt; MI: Myocardial infarction; MNP: Magnetic nanoparticles; MSC: Mesenchymal stem cell; NF-κB: Nuclear factor kappa B; PD: Parkinson’s disease; PDGF: Platelet-derived growth factor; RT-PCR: Real-time polymerase chain reaction; Runx2: Runt-related transcription factor 2; SDF-1a: Stromal cell derived factor 1-alpha; SKM: Skeletal myoblasts; SMC: Smooth muscle cell; TRPV1: Transient receptor potential vanilloid 1; TSB: Transforming growth factor-β, sphingosylphosphorylcholine, and bone morphogenetic protein-4; VEGF-A: Vascular endothelial growth factor A; αSMA: Alpha smooth muscle actin; β-MHC: Beta myosin heavy chain; κC: κ-carrageenan.