• French A, Bravery C, Smith J, Chandra A, Archibald P, Gold JD, Artzi N, Kim HW, Barker RW, Meissner A, Wu JC, Knowles JC, Williams D, García-Cardeña G, Sipp D, Oh S, Loring JF, Rao MS, Reeve B, Wall I, Carr AJ, Bure K, Stacey G, Karp JM, Snyder EY, Brindley DA. Enabling consistency in pluripotent stem cell-derived products for research and development and clinical applications through material standards. Stem Cells Transl Med. 2015 Mar;4(3):217-23. PubMed: 25650438. Categories: RepleniSENS

    Enabling consistency in pluripotent stem cell-derived products for research and development and clinical applications through material standards.

    Stem Cells Transl Med. 2015 Mar;4(3):217-23.

    Enabling consistency in pluripotent stem cell-derived products for research and development and clinical applications through material standards.

    French A, Bravery C, Smith J, Chandra A, Archibald P, Gold JD, Artzi N, Kim HW, Barker RW, Meissner A, Wu JC, Knowles JC, Williams D, García-Cardeña G, Sipp D, Oh S, Loring JF, Rao MS, Reeve B, Wall I, Carr AJ, Bure K, Stacey G, Karp JM, Snyder EY, Brindley DA.

    Abstract

    Abstract:

    There is a need for physical standards (reference materials) to ensure both reproducibility and consistency in the production of somatic cell types from human pluripotent stem cell (hPSC) sources. We have outlined the need for reference materials (RMs) in relation to the unique properties and concerns surrounding hPSC-derived products and suggest in-house approaches to RM generation relevant to basic research, drug screening, and therapeutic applications. hPSCs have an unparalleled potential as a source of somatic cells for drug screening, disease modeling, and therapeutic application. Undefined variation and product variability after differentiation to the lineage or cell type of interest impede efficient translation and can obscure the evaluation of clinical safety and efficacy. Moreover, in the absence of a consistent population, data generated from in vitro studies could be unreliable and irreproducible. Efforts to devise approaches and tools that facilitate improved consistency of hPSC-derived products, both as development tools and therapeutic products, will aid translation. Standards exist in both written and physical form; however, because many unknown factors persist in the field, premature written standards could inhibit rather than promote innovation and translation. We focused on the derivation of physical standard RMs. We outline the need for RMs and assess the approaches to in-house RM generation for hPSC-derived products, a critical tool for the analysis and control of product variation that can be applied by researchers and developers. We then explore potential routes for the generation of RMs, including both cellular and noncellular materials and novel methods that might provide valuable tools to measure and account for variation. Multiparametric techniques to identify "signatures" for therapeutically relevant cell types, such as neurons and cardiomyocytes that can be derived from hPSCs, would be of significant utility, although physical RMs will be required for clinical purposes.

  • Silva M, Daheron L, Hurley H, Bure K, Barker R, Carr AJ, Williams D, Kim HW, French A, Coffey PJ, Cooper-White JJ, Reeve B, Rao M, Snyder EY, Ng KS, Mead BE, Smith JA, Karp JM, Brindley DA, Wall I. Generating iPSCs: Translating Cell Reprogramming Science into Scalable and Robust Biomanufacturing Strategies. Cell Stem Cell. 2015 Jan 8;16(1):13-7. PubMed: 25575079. Categories: RepleniSENS

    Generating iPSCs: Translating Cell Reprogramming Science into Scalable and Robust Biomanufacturing Strategies.

    Cell Stem Cell. 2015 Jan 8;16(1):13-7.

    Generating iPSCs: Translating Cell Reprogramming Science into Scalable and Robust Biomanufacturing Strategies.

    Silva M, Daheron L, Hurley H, Bure K, Barker R, Carr AJ, Williams D, Kim HW, French A, Coffey PJ, Cooper-White JJ, Reeve B, Rao M, Snyder EY, Ng KS, Mead BE, Smith JA, Karp JM, Brindley DA, Wall I.

    Abstract

    Abstract:

    Induced pluripotent stem cells (iPSCs) have the potential to transform drug discovery and healthcare in the 21(st) century. However, successful commercialization will require standardized manufacturing platforms. Here we highlight the need to define standardized practices for iPSC generation and processing and discuss current challenges to the robust manufacture of iPSC products.

  • Boura JS, Vance M, Yin W, Madeira C, Lobato da Silva C, Porada CD, Almeida-Porada G. Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells. Mol Ther Methods Clin Dev. 2014 Sep;2014(1). pii: 14041. PubMed: 25279386. Categories: OncoSENS, RepleniSENS

    Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells.

    Mol Ther Methods Clin Dev. 2014 Sep;2014(1). pii: 14041.

    Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells.

    Boura JS, Vance M, Yin W, Madeira C, Lobato da Silva C, Porada CD, Almeida-Porada G.

    Abstract

    Abstract:

    Mesenchymal stromal cells (MSC) constitutively express low levels of human leukocyte antigen-G (HLA-G), which has been shown to contribute to their immunomodulatory and anti-inflammatory properties. Here, we hypothesized that overexpression of HLA-G on bone marrow-derived MSC would improve their immunomodulatory function, thus increasing their therapeutic potential. Therefore, we investigated which gene transfer system is best suited for delivering this molecule while maintaining its immuno-modulatory effects. We performed a side-by-side comparison between three nonviral plasmid-based platforms (pmax-HLA-G1; MC-HLA-G1; pEP-HLA-G1) and a viral system (Lv-HLA-G1) using gene transfer parameters that yielded similar levels of HLA-G1-expressing MSC. Natural killer (NK) cell-mediated lysis assays and T cell proliferation assays showed that MSC modified with the HLA-G1 expressing viral vector had significantly lower susceptibility to NK-lysis and significantly reduced T cell proliferation when compared to nonmodified cells or MSC modified with plasmid. We also show that, in plasmid-modified MSC, an increase in Toll-like receptor (TLR)9 expression is the mechanism responsible for the abrogation of HLA-G1's immunomodulatory effect. Although MSC can be efficiently modified to overexpress HLA-G1 using viral and nonviral strategies, only viral-based delivery of HLA-G1 is suitable for improvement of MSC's immunomodulatory properties.

  • Elabd C, Cousin W, Upadhyayula P, Chen RY, Chooljian MS, Li J, Kung S, Jiang KP, Conboy IM. Oxytocin is an age-specific circulating hormone that is necessary for muscle maintenance and regeneration. Nat Commun. 2014 Jun 10;5:4082. doi: 10.1038/ncomms5082. PubMed: 24915299. Categories: RepleniSENS

    Oxytocin is an age-specific circulating hormone that is necessary for muscle maintenance and regeneration.

    Nat Commun. 2014 Jun 10;5:4082. doi: 10.1038/ncomms5082.

    Oxytocin is an age-specific circulating hormone that is necessary for muscle maintenance and regeneration.

    Elabd C, Cousin W, Upadhyayula P, Chen RY, Chooljian MS, Li J, Kung S, Jiang KP, Conboy IM.

    Abstract

    Abstract:

    The regenerative capacity of skeletal muscle declines with age. Previous studies suggest that this process can be reversed by exposure to young circulation; however, systemic age-specific factors responsible for this phenomenon are largely unknown. Here we report that oxytocin-a hormone best known for its role in lactation, parturition and social behaviours-is required for proper muscle tissue regeneration and homeostasis, and that plasma levels of oxytocin decline with age. Inhibition of oxytocin signalling in young animals reduces muscle regeneration, whereas systemic administration of oxytocin rapidly improves muscle regeneration by enhancing aged muscle stem cell activation/proliferation through activation of the MAPK/ERK signalling pathway. We further show that the genetic lack of oxytocin does not cause a developmental defect in muscle but instead leads to premature sarcopenia. Considering that oxytocin is an FDA-approved drug, this work reveals a potential novel and safe way to combat or prevent skeletal muscle ageing.

  • Chen Y, Ma X, Zhang M, Wang X, Wang C, Wang H, Guo P, Yuan W, Rudolph KL, Zhan Q, Ju Z. Gadd45a regulates hematopoietic stem cell stress responses in mice. Blood. 2014 Feb 6;123(6):851-62. doi: 10.1182/blood-2013-05-504084. PubMed: 24371210. Categories: RepleniSENS

    Gadd45a regulates hematopoietic stem cell stress responses in mice.

    Blood. 2014 Feb 6;123(6):851-62. doi: 10.1182/blood-2013-05-504084.

    Gadd45a regulates hematopoietic stem cell stress responses in mice.

    Chen Y, Ma X, Zhang M, Wang X, Wang C, Wang H, Guo P, Yuan W, Rudolph KL, Zhan Q, Ju Z.

    Abstract

    Abstract:

    Gadd45a has been involved in DNA damage response and in many malignancies, including leukemia. However, the function of Gadd45a in hematopoietic stem cells (HSCs) remains unknown. Here, we reported that Gadd45a-deficient (Gadd45a(-/-)) mice showed a normal hematologic phenotype under homeostatic conditions. However, following 5-fluorouracil treatment, Gadd45a(-/-) HSCs exhibited a faster recovery, associated with an increase in the proliferation rate. Interestingly, young Gadd45a(-/-) HSCs showed enhanced reconstitution ability in serial transplantation. Following ionizing radiation (IR), young Gadd45a(-/-) HSCs exhibited an increased resistance to IR-induced DNA damage, associated with a decrease in the apoptosis rate and delayed DNA repair. The significantly higher level of DNA damage in Gadd45a(-/-) HSCs ultimately promoted B-cell leukemia in further transplanted recipient mice. In old mice, Gadd45a(-/-) HSCs were functionally equal to wild-type HSCs but exhibited more DNA damage accumulation and increased sensitivity to IR than wild-type HSCs. In conclusion, Gadd45a plays a significant role in HSC stress responses. Gadd45a deficiency leads to DNA damage accumulation and impairment in apoptosis after exposure to IR, which increases the susceptibility of leukemogenesis.

  • Rohani L, Johnson AA, Arnold A, Stolzing A. The aging signature: a hallmark of induced pluripotent stem cells? Aging Cell 2014;13(1):2-7. PubMed: 24256351. Categories: RepleniSENS

    The aging signature: a hallmark of induced pluripotent stem cells?

    Aging Cell 2014;13(1):2-7.

    The aging signature: a hallmark of induced pluripotent stem cells?

    Rohani L, Johnson AA, Arnold A, Stolzing A.

    Abstract

    Abstract:

    The discovery that somatic cells can be induced into a pluripotent state by the expression of reprogramming factors has enormous potential for therapeutics and human disease modeling. With regard to aging and rejuvenation, the reprogramming process resets an aged, somatic cell to a more youthful state, elongating telomeres, rearranging the mitochondrial network, reducing oxidative stress, restoring pluripotency, and making numerous other alterations. The extent to which induced pluripotent stem cell (iPSC)s mime embryonic stem cells is controversial, however, as iPSCs have been shown to harbor an epigenetic memory characteristic of their tissue of origin which may impact their differentiation potential. Furthermore, there are contentious data regarding the extent to which telomeres are elongated, telomerase activity is reconstituted, and mitochondria are reorganized in iPSCs. Although several groups have reported that reprogramming efficiency declines with age and is inhibited by genes upregulated with age, others have successfully generated iPSCs from senescent and centenarian cells. Mixed findings have also been published regarding whether somatic cells generated from iPSCs are subject to premature senescence. Defects such as these would hinder the clinical application of iPSCs, and as such, more comprehensive testing of iPSCs and their potential aging signature should be conducted.

  • Chen Y, Yang R, Guo P, Ju Z. Gadd45a deletion aggravates hematopoietic stem cell dysfunction in ATM-deficient mice. Protein Cell. 2014 Jan;5(1):80-9. doi: 10.1007/s13238-013-0017-9. PubMed: 24474198. Categories: RepleniSENS

    Gadd45a deletion aggravates hematopoietic stem cell dysfunction in ATM-deficient mice.

    Protein Cell. 2014 Jan;5(1):80-9. doi: 10.1007/s13238-013-0017-9.

    Gadd45a deletion aggravates hematopoietic stem cell dysfunction in ATM-deficient mice.

    Chen Y, Yang R, Guo P, Ju Z.

    Abstract

    Abstract:

    Ataxia telangiectasia mutated (ATM) kinase plays an essential role in the maintenance of genomic stability. ATM-deficient (ATM(-/-)) mice exhibit hematopoietic stem cell (HSC) dysfunction and a high incidence of lymphoma. Gadd45a controls cell cycle arrest, apoptosis and DNA repair, and is involved in the ATM-p53 mediated DNA damage response. However, the role of Gadd45a in regulating the functionality of ATM(-/-) HSCs is unknown. Here we report that Gadd45a deletion did not rescue the defects of T-cells and B-cells development in ATM(-/-) mice. Instead, ATM and Gadd45a double knockout (ATM(-/-) Gadd45a(-/-)) HSCs exhibited an aggravated defect in long-term self-renewal capacity compared to ATM(-/-) HSCs in HSC transplantation experiments. Further experiments revealed that the aggravated defect of ATM(-/-) Gadd45a(-/-) HSCs was due to a reduction of cell proliferation, associated with an accumulation of DNA damage and subsequent activation of DNA damage response including an up-regulation of p53-p21 signaling pathway. Additionally, ATM(-/-) Gadd45a(-/-) mice showed an increased incidence of hematopoietic malignancies, as well as an increased rate of metastasis than ATM(-/-) mice. In conclusion, Gadd45a deletion aggravated the DNA damage accumulation, which subsequently resulted in a further impaired self-renewal capacity and an increased malignant transformation in ATM(-/-) HSCs.

  • Zhang J, Yang R, Zhou D, Rudolph KL, Meng A, Ju Z. Exonuclease 1 is essential for maintaining genomic stability and the proliferative capacity of neural but not hematopoietic stem cells. Stem Cell Res. 2014 Jan;12(1):250-9. doi: 10.1016/j.scr.2013.11.001. PubMed: 24280419. Categories: RepleniSENS

    Exonuclease 1 is essential for maintaining genomic stability and the proliferative capacity of neural but not hematopoietic stem cells.

    Stem Cell Res. 2014 Jan;12(1):250-9. doi: 10.1016/j.scr.2013.11.001.

    Exonuclease 1 is essential for maintaining genomic stability and the proliferative capacity of neural but not hematopoietic stem cells.

    Zhang J, Yang R, Zhou D, Rudolph KL, Meng A, Ju Z.

    Abstract

    Abstract:

    Exonuclease 1 (Exo1) has been implicated in the regulation of DNA damage responses in stem cells with dysfunctional telomeres. However, it is unclear whether Exo1-mediated DNA maintenance pathways play a role in the maintenance of genomic stability and the self-renewal of tissue stem cells in mice with functional telomeres. Here, we analyzed the proliferative capacity of neural stem cells (NSCs) and hematopoietic stem cells (HSCs) from Exo1(-/-) mice. Our study shows that Exo1 deficiency impairs the maintenance of genomic stability and proliferative capacity in NSCs but not HSCs. In line with these results, we detected a decrease in proliferation and an up-regulation of p21 expression levels in Exo1-deficient NSCs but not Exo1-deficient HSCs. Our data provide experimental evidence that Exo1 deficiency has a differential impact on the homeostasis and proliferative capacity of tissue stem cells in the brain and bone marrow, suggesting that different tissue stem cells utilize distinct mechanisms for maintaining their genomic stability. Our current study provides important insight into the role of Exo1-mediated DNA maintenance pathways in the maintenance of genomic stability and the proliferative capacity of tissue stem cells.

  • Brindley DA, Davie NL, Sahlman WA, Bonfiglio GA, Culme-Seymour EJ, Reeve BC, Mason C. Promising growth and investment in the cell therapy industry during the first quarter of 2012. Cell Stem Cell. 2012 May 4;10(5):492-6. PubMed: 22560072. Categories: RepleniSENS

    Promising growth and investment in the cell therapy industry during the first quarter of 2012.

    Cell Stem Cell. 2012 May 4;10(5):492-6.

    Promising growth and investment in the cell therapy industry during the first quarter of 2012.

    Brindley DA, Davie NL, Sahlman WA, Bonfiglio GA, Culme-Seymour EJ, Reeve BC, Mason C.

    Abstract

    Abstract:

    In the first quarter of 2012, publicly traded companies in the cell-based therapy industry continued to show promising overall growth. Highlights included $85 million in new capital investment and steady clinical trial progress.

  • Brindley D, Moorthy K, Lee JH, Mason C, Kim HW, Wall I. Bioprocess forces and their impact on cell behavior: implications for bone regeneration therapy. J Tissue Eng. 2011;2011:620247. PubMed: 21904661. Categories: RepleniSENS

    Bioprocess forces and their impact on cell behavior: implications for bone regeneration therapy.

    J Tissue Eng. 2011;2011:620247.

    Bioprocess forces and their impact on cell behavior: implications for bone regeneration therapy.

    Brindley D, Moorthy K, Lee JH, Mason C, Kim HW, Wall I.

    Abstract

    Abstract:

    Bioprocess forces such as shear stress experienced during routine cell culture are considered to be harmful to cells. However, the impact of physical forces on cell behavior is an area of growing interest within the tissue engineering community, and it is widely acknowledged that mechanical stimulation including shear stress can enhance osteogenic differentiation. This paper considers the effects of bioprocess shear stress on cell responses such as survival and proliferation in several contexts, including suspension-adapted cells used for recombinant protein and monoclonal antibody manufacture, adherent cells for therapy in suspension, and adherent cells attached to their growth substrates. The enhanced osteogenic differentiation that fluid flow shear stress is widely found to induce is discussed, along with the tissue engineering of mineralized tissue using perfusion bioreactors. Recent evidence that bioprocess forces produced during capillary transfer or pipetting of cell suspensions can enhance osteogenic responses is also discussed.