Adipose-derived mesenchymal stem cells(MSCs)are a superior cell source for bone tissue engineering

Effective bone regeneration through tissue engineering requires a combination of osteogenic progenitors,osteoinductive biofactors and biocompatible scaffold materials.Mesenchymal stem cells(MSCs)represent the most promising seed cells for bone tissue engineering.As multipotent stem cells that can self-renew and differentiate into multiple lineages including bone and fat,MSCs can be isolated from numerous tissues and exhibit varied differentiation potential.To identify an optimal progenitor cell source for bone tissue engineering,we analyzed the proliferative activity and osteogenic potential of four commonly-used mouse MSC sources,including immortalized mouse embryonic fibroblasts(iMEF),immortalized mouse bone marrow stromal stem cells(imBMSC),immortalized mouse calvarial mesenchymal progenitors(iCAL),and immortalized mouse adipose-derived mesenchymal stem cells(iMAD).We found that iMAD exhibited highest osteogenic and adipogenic capabilities upon BMP9 stimulation in vitro,whereas iMAD and iCAL exhibited highest osteogenic capability in BMP9-induced ectopic osteogenesis and critical-sized calvarial defect repair.Transcriptomic analysis revealed that,while each MSC line regulated a distinct set of target genes upon BMP9 stimulation,all MSC lines underwent osteogenic differentiation by regulating osteogenesis-related signaling including Wnt,TGF-β,PI3K/AKT,MAPK,Hippo and JAK-STAT pathways.Collectively,our results demonstrate that adipose-derived MSCs represent optimal progenitor sources for cell-based bone tissue engineering.

Syrosingopine,an anti-hypertensive drug and lactate transporter(MCT1/4)inhibitor,activates hepatic stellate cells and exacerbates liver fibrosis in a mouse model

Syrosingopine is an anti-hypertensive drug and can cause high intracellular lactate levels and end-product inhibition of lactate dehydrogenase by inhibiting the lactate transporters MCT1 and MCT4.Previous studies have shown that syrosingopine plays an essential role in the process of glycolytic blockade,ATP depletion,and cell death in cancer due to high intracellular levels of lactate.

A simplified noncryogenic strategy to transport mesenchymal stem cells: Potential applications in cell therapy and regenerative medicine

With the rapid advances in stem cell research and po-tential cell-based therapies,there is an urgent need to develop safe and reliable cell transport strategies.Except for autologous stem cell-based therapies,allogeneic stem cell therapies and ex vivo genetically engineered cell therapies would require safe,efficient,and reliable cell preservation and transport methods.

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in develop-ment and adult tissue homeostasis across species.Wnt proteins are secreted,lipid-modified signaling molecules that activate the canonical(β-catenin dependent)and non-canonical(β-catenin independent)Wnt signaling pathways.Cellular behaviors such as proliferation,differ-entiation,maturation,and proper body-axis specification are carried out by the canonical pathway,which is the best characterized of the known Wnt signaling paths.Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues.This includes but is not limited to embryonic,hematopoietic,mesenchymal,gut,neural,and epidermal stem cells.Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties.Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders.Not surprisingly,aberrant Wnt signaling is also associated with a wide variety of diseases,including cancer.Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation,epithelial-mesenchymal transition,and metastasis.Altogether,advances in the understand-ing of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway.Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt,this review aims to summarize the cur-rent knowledge of Wnt signaling in stem cells,aberrations to the Wnt pathway associated with diseases,and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

GAPDH suppresses adenovirus-induced oxidative stress and enables a superfast production of recombinant adenovirus

Recombinant adenovirus(rAdV)is a commonly used vector system for gene transfer.Efficient initial packaging and subsequent production of rAdV remains time-consuming and labor-intensive,possibly attributable to rAdv infection-associated oxidative stress and reactive oxygen species(ROS)production.Here,we show that exogenous GAPDH expression mitigates adenovirus-induced ROS-associated apoptosis in HEK293 cells,and expedites adenovirus production.By stably overexpressing GAPDH in HEK293(293G)and 293pTP(293GP)cells,respectively,we demonstrated that rAdV-induced RoS production and cell apoptosis were significantly suppressed in 293G and 293GP cells.Transfection of 293G cells with adenoviral plasmid pAd-G2Luc yielded much higher titers of Ad-G2Luc at day 7 than that in HEK293 cells.Similarly,Ad-G2Luc was amplified more efficiently in 293G than in HEK293 cells.We further showed that transfection of 293GP cells with pAd-G2Luc produced much higher titers of Ad-G2Luc at day 5 than that of 293pTP cells.293GP cells amplified the Ad-G2Luc much more efficiently than 293pTP cells,indicating that exogenous GAPDH can further augment pTP-enhanced adenovirus production.These results demonstrate that exogenous GAPDH can effectively suppress adenovirus-induced ROS and thus accelerate adenovirus production.Therefore,the engineered 293GP cells represent a superfast rAdV production system for adenovirus-based gene transfer and gene therapy.

SV40 large T antigen-induced immortalization reprograms mouse cardiomyocyte progenitors with mesenchymal stem cell characteristics and osteogenic potential

While progenitor cell-based cardiomyocyte regeneration holds great promise of repairing an injured heart,primary cardiomyogenic progenitors(CPs)have a limited life span in culture,hampering the use of CPs for in vitro and in vivo studies.We previously isolated primary CPs from mouse E15.5 fetal heart,and reversibly immortalized them with SV40 large T antigen(SV40 LTA),resulting in immortalized CPs(iCPs),which maintain long-term proliferation and ex-press cardiomyogenic markers and retain differentiation potential under appropriate differentiation conditions.

Bone Morphogenic Protein 9(BMP9)/Growth Differentiation Factor 2(GDF2)modulates mouse adult hippocampal neurogenesis by regulating the survival of early neural progenitors

Adult neurogenesis occurs in two specialized regions of the mammalian brain,the subventricular zone(SVZ)and the subgranular zone(SGZ)of the dentate gyrus(DG).^(1)Adult hippocampal neural stem cells(NSCs),referred to as Type 1 cells represented by radial glia-like cells(RGLs),generate Type 2 cells that are divided into Type 2a and Type 2 b subpopulations,the latter of which give rise to Type 3 cells(neuroblasts).

Reversibly immortalized keratinocytes(iKera)facilitate re-epithelization and skin wound healing:Potential applications in cell-based skin tissue engineering

Skin injury is repaired through a multi-phase wound healing process of tissue granulation and re-epithelialization.Any failure in the healing process may lead to chronic non-healing wounds or abnormal scar formation.Although significant progress has been made in developing novel scaffolds and/or cell-based therapeutic strategies to promote wound healing,effective management of large chronic skin wounds remains a clinical challenge.Keratinocytes are critical to re-epithelialization and wound healing.Here,we investigated whether exogenous keratinocytes,in combination with a citrate-based scaffold,enhanced skin wound healing.We first established reversibly immortalized mouse keratinocytes(iKera),and confirmed that the iKera cells expressed keratinocyte markers,and were responsive to UVB treatment,and were non-tumorigenic.In a proof-of-principle experiment,we demonstrated that iKera cells embedded in citrate-based scaffold PPCN provided more effective re-epithelialization and cutaneous wound healing than that of either PPCN or iKera cells alone,in a mouse skin wound model.Thus,these results demonstrate that iKera cells may serve as a valuable skin epithelial source when,combining with appropriate biocompatible scaffolds,to investigate cutaneous wound healing and skin regeneration.