Publications by authors named "Panagiotis Mistriotis"

21 Publications

  • Page 1 of 1

Kidney epithelial cells are active mechano-biological fluid pumps.

Nat Commun 2022 Apr 28;13(1):2317. Epub 2022 Apr 28.

Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States.

The role of mechanical forces driving kidney epithelial fluid transport and morphogenesis in kidney diseases is unclear. Here, using a microfluidic platform to recapitulate fluid transport activity of kidney cells, we report that renal epithelial cells can actively generate hydraulic pressure gradients across the epithelium. The fluidic flux declines with increasing hydraulic pressure until a stall pressure, in a manner similar to mechanical fluid pumps. For normal human kidney cells, the fluidic flux is from apical to basal, and the pressure is higher on the basal side. For human Autosomal Dominant Polycystic Kidney Disease cells, the fluidic flux is reversed from basal to apical. Molecular and proteomic studies reveal that renal epithelial cells are sensitive to hydraulic pressure gradients, changing gene expression profiles and spatial arrangements of ion exchangers and the cytoskeleton in different pressure conditions. These results implicate mechanical force and hydraulic pressure as important variables during kidney function and morphological change, and provide insights into pathophysiological mechanisms underlying the development and transduction of hydraulic pressure gradients.
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http://dx.doi.org/10.1038/s41467-022-29988-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9050750PMC
April 2022

The fluid shear stress sensor TRPM7 regulates tumor cell intravasation.

Sci Adv 2021 Jul 9;7(28). Epub 2021 Jul 9.

Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA.

Tumor cell intravasation preferentially occurs in regions of low fluid shear because high shear is detrimental to tumor cells. Here, we describe a molecular mechanism by which cells avoid high shear during intravasation. The transition from migration to intravasation was modeled using a microfluidic device where cells migrating inside longitudinal tissue-like microchannels encounter an orthogonal channel in which fluid flow induces physiological shear stresses. This approach was complemented with intravital microscopy, patch-clamp, and signal transduction imaging techniques. Fluid shear-induced activation of the transient receptor potential melastatin 7 (TRPM7) channel promotes extracellular calcium influx, which then activates RhoA/myosin-II and calmodulin/IQGAP1/Cdc42 pathways to coordinate reversal of migration direction, thereby avoiding shear stress. Cells displaying higher shear sensitivity due to higher TRPM7 activity levels intravasate less efficiently and establish less invasive metastatic lesions. This study provides a mechanistic interpretation for the role of shear stress and its sensor, TRPM7, in tumor cell intravasation.
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http://dx.doi.org/10.1126/sciadv.abh3457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270498PMC
July 2021

A Procarcinogenic Colon Microbe Promotes Breast Tumorigenesis and Metastatic Progression and Concomitantly Activates Notch and β-Catenin Axes.

Cancer Discov 2021 05 6;11(5):1138-1157. Epub 2021 Jan 6.

Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland.

The existence of distinct breast microbiota has been recently established, but their biological impact in breast cancer remains elusive. Focusing on the shift in microbial community composition in diseased breast compared with normal breast, we identified the presence of in cancerous breast. Mammary gland as well as gut colonization with enterotoxigenic (ETBF), which secretes toxin (BFT), rapidly induces epithelial hyperplasia in the mammary gland. Breast cancer cells exposed to BFT exhibit "BFT memory" from the initial exposure. Intriguingly, gut or breast duct colonization with ETBF strongly induces growth and metastatic progression of tumor cells implanted in mammary ducts, in contrast to nontoxigenic . This work sheds light on the oncogenic impact of a procarcinogenic colon bacterium ETBF on breast cancer progression, implicates the β-catenin and Notch1 axis as its functional mediators, and proposes the concept of "BFT memory" that can have far-reaching biological implications after initial exposure to ETBF. SIGNIFICANCE: is an inhabitant of breast tissue, and gut or mammary duct colonization with ETBF triggers epithelial hyperplasia and augments breast cancer growth and metastasis. Short-term exposure to BFT elicits a "BFT memory" with long-term implications, functionally mediated by the β-catenin and Notch1 pathways..
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http://dx.doi.org/10.1158/2159-8290.CD-20-0537DOI Listing
May 2021

Myosin 10 Regulates Invasion, Mitosis, and Metabolic Signaling in Glioblastoma.

iScience 2020 Dec 13;23(12):101802. Epub 2020 Nov 13.

Department of Cancer Biology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA.

Invasion and proliferation are defining phenotypes of cancer, and in glioblastoma blocking one stimulates the other, implying that effective therapy must inhibit both, ideally through a single target that is also dispensable for normal tissue function. The molecular motor myosin 10 meets these criteria. Myosin 10 knockout mice can survive to adulthood, implying that normal cells can compensate for its loss; its deletion impairs invasion, slows proliferation, and prolongs survival in murine models of glioblastoma. Myosin 10 deletion also enhances tumor dependency on the DNA damage and the metabolic stress responses and induces synthetic lethality when combined with inhibitors of these processes. Our results thus demonstrate that targeting myosin 10 is active against glioblastoma by itself, synergizes with other clinically available therapeutics, may have acceptable side effects in normal tissues, and has potential as a heretofore unexplored therapeutic approach for this disease.
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http://dx.doi.org/10.1016/j.isci.2020.101802DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7702012PMC
December 2020

Dorsoventral polarity directs cell responses to migration track geometries.

Sci Adv 2020 07 31;6(31):eaba6505. Epub 2020 Jul 31.

Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.

How migrating cells differentially adapt and respond to extracellular track geometries remains unknown. Using intravital imaging, we demonstrate that invading cells exhibit dorsoventral (top-to-bottom) polarity in vivo. To investigate the impact of dorsoventral polarity on cell locomotion through different confining geometries, we fabricated microchannels of fixed cross-sectional area, albeit with distinct aspect ratios. Vertical confinement, exerted along the dorsoventral polarity axis, induces myosin II-dependent nuclear stiffening, which results in RhoA hyperactivation at the cell poles and slow bleb-based migration. In lateral confinement, directed perpendicularly to the dorsoventral polarity axis, the absence of perinuclear myosin II fails to increase nuclear stiffness. Hence, cells maintain basal RhoA activity and display faster mesenchymal migration. In summary, by integrating microfabrication, imaging techniques, and intravital microscopy, we demonstrate that dorsoventral polarity, observed in vivo and in vitro, directs cell responses in confinement by spatially tuning RhoA activity, which controls bleb-based versus mesenchymal migration.
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http://dx.doi.org/10.1126/sciadv.aba6505DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7399493PMC
July 2020

Confinement hinders motility by inducing RhoA-mediated nuclear influx, volume expansion, and blebbing.

J Cell Biol 2019 12 5;218(12):4093-4111. Epub 2019 Nov 5.

Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD

Cells migrate in vivo through complex confining microenvironments, which induce significant nuclear deformation that may lead to nuclear blebbing and nuclear envelope rupture. While actomyosin contractility has been implicated in regulating nuclear envelope integrity, the exact mechanism remains unknown. Here, we argue that confinement-induced activation of RhoA/myosin-II contractility, coupled with LINC complex-dependent nuclear anchoring at the cell posterior, locally increases cytoplasmic pressure and promotes passive influx of cytoplasmic constituents into the nucleus without altering nuclear efflux. Elevated nuclear influx is accompanied by nuclear volume expansion, blebbing, and rupture, ultimately resulting in reduced cell motility. Moreover, inhibition of nuclear efflux is sufficient to increase nuclear volume and blebbing on two-dimensional surfaces, and acts synergistically with RhoA/myosin-II contractility to further augment blebbing in confinement. Cumulatively, confinement regulates nuclear size, nuclear integrity, and cell motility by perturbing nuclear flux homeostasis via a RhoA-dependent pathway.
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http://dx.doi.org/10.1083/jcb.201902057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6891075PMC
December 2019

Cell sensing and decision-making in confinement: The role of TRPM7 in a tug of war between hydraulic pressure and cross-sectional area.

Sci Adv 2019 07 24;5(7):eaaw7243. Epub 2019 Jul 24.

Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.

How cells sense hydraulic pressure and make directional choices in confinement remains elusive. Using trifurcating Ψ-like microchannels of different hydraulic resistances and cross-sectional areas, we discovered that the TRPM7 ion channel is the critical mechanosensor, which directs decision-making of blebbing cells toward channels of lower hydraulic resistance irrespective of their cross-sectional areas. Hydraulic pressure-mediated TRPM7 activation triggers calcium influx and supports a thicker cortical actin meshwork containing an elevated density of myosin-IIA. Cortical actomyosin shields cells against external forces and preferentially directs cell entrance in low resistance channels. Inhibition of TRPM7 function or actomyosin contractility renders cells unable to sense different resistances and alters the decision-making pattern to cross-sectional area-based partition. Cell distribution in microchannels is captured by a mathematical model based on the maximum entropy principle using cortical actin as a key variable. This study demonstrates the unique role of TRPM7 in controlling decision-making and navigating migration in complex microenvironments.
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http://dx.doi.org/10.1126/sciadv.aaw7243DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6656542PMC
July 2019

Restoring extracellular matrix synthesis in senescent stem cells.

FASEB J 2019 10 9;33(10):10954-10965. Epub 2019 Jul 9.

Department of Chemical and Biological Engineering, University at Buffalo, Buffalo, New York, USA.

Collagen type III (COL3) is one of the 3 major collagens in the body, and loss of expression or mutations in the gene have been associated with the onset of vascular diseases such the Ehlers-Danlos syndrome. Previous work reported a significant reduction of COL3 in tissues such as skin and vessels with aging. In agreement, we found that COL3 was significantly reduced in senescent human mesenchymal stem cells and myofibroblasts derived from patients with Hutchinson-Gilford progeria syndrome, a premature aging syndrome. Most notably, we discovered that ectopic expression of the embryonic transcription factor Nanog homeobox (NANOG) restored COL3 expression by restoring the activity of the TGF-β pathway that was impaired in senescent cells. RNA sequencing analysis showed that genes associated with the activation of the TGF-β pathway were up-regulated, whereas negative regulators of the pathway were down-regulated upon NANOG expression. Chromatin immunoprecipitation sequencing and immunoprecipitation experiments revealed that NANOG bound to the mothers against decapentaplegic (SMAD)2 and SMAD3 promoters, in agreement with increased expression and phosphorylation levels of both proteins. Using chemical inhibition, short hairpin RNA knockdown, and gain of function approaches, we established that both SMAD2 and SMAD3 were necessary to mediate the effects of NANOG, but SMAD3 overexpression was also sufficient for COL3 production. In summary, NANOG restored production of COL3, which was impaired by cellular aging, suggesting novel strategies to restore the impaired extracellular matrix production and biomechanical function of aged tissues, with potential implications for regenerative medicine and anti-aging treatments.-Rong, N., Mistriotis, P., Wang, X., Tseropoulos, G., Rajabian, N., Zhang, Y., Wang, J., Liu, S., Andreadis, S. T. Restoring extracellular matrix synthesis in senescent stem cells.
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http://dx.doi.org/10.1096/fj.201900377RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6766659PMC
October 2019

A microfluidic assay for the quantification of the metastatic propensity of breast cancer specimens.

Nat Biomed Eng 2019 06 6;3(6):452-465. Epub 2019 May 6.

Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA.

The challenge of predicting which patients with breast cancer will develop metastases leads to the overtreatment of patients with benign disease and to the inadequate treatment of aggressive cancers. Here, we report the development and testing of a microfluidic assay that quantifies the abundance and proliferative index of migratory cells in breast cancer specimens, for the assessment of their metastatic propensity and for the rapid screening of potential antimetastatic therapeutics. On the basis of the key roles of cell motility and proliferation in cancer metastasis, the device accurately predicts the metastatic potential of breast cancer cell lines and of patient-derived xenografts. Compared with unsorted cancer cells, highly motile cells isolated by the device exhibited similar tumourigenic potential but markedly increased metastatic propensity in vivo. RNA sequencing of the highly motile cells revealed an enrichment of motility-related and survival-related genes. The approach might be developed into a companion assay for the prediction of metastasis in patients and for the selection of effective therapeutic regimens.
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http://dx.doi.org/10.1038/s41551-019-0400-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6563615PMC
June 2019

A Direct Podocalyxin-Dynamin-2 Interaction Regulates Cytoskeletal Dynamics to Promote Migration and Metastasis in Pancreatic Cancer Cells.

Cancer Res 2019 06 11;79(11):2878-2891. Epub 2019 Apr 11.

Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, Maryland.

The sialoglycoprotein podocalyxin is absent in normal pancreas but is overexpressed in pancreatic cancer and is associated with poor clinical outcome. Here, we investigate the role of podocalyxin in migration and metastasis of pancreatic adenocarcinomas using SW1990 and Pa03c as cell models. Although ezrin is regarded as a cytoplasmic binding partner of podocalyxin that regulates actin polymerization via Rac1 or RhoA, we did not detect podocalyxin-ezrin association in pancreatic cancer cells. Moreover, depletion of podocalyxin did not alter actin dynamics or modulate Rac1 and RhoA activities in pancreatic cancer cells. Using mass spectrometry, bioinformatics analysis, coimmunoprecipitation, and pull-down assays, we discovered a novel, direct binding interaction between the cytoplasmic tail of podocalyxin and the large GTPase dynamin-2 at its GTPase, middle, and pleckstrin homology domains. This podocalyxin-dynamin-2 interaction regulated microtubule growth rate, which in turn modulated focal adhesion dynamics and ultimately promoted efficient pancreatic cancer cell migration via microtubule- and Src-dependent pathways. Depletion of podocalyxin in a hemispleen mouse model of pancreatic cancer diminished liver metastasis without altering primary tumor size. Collectively, these findings reveal a novel mechanism by which podocalyxin facilitates pancreatic cancer cell migration and metastasis. SIGNIFICANCE: These findings reveal that a novel interaction between podocalyxin and dynamin-2 promotes migration and metastasis of pancreatic cancer cells by regulating microtubule and focal adhesion dynamics.
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http://dx.doi.org/10.1158/0008-5472.CAN-18-3369DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6548656PMC
June 2019

Exposing Cell-Itary Confinement: Understanding the Mechanisms of Confined Single Cell Migration.

Adv Exp Med Biol 2018;1092:139-157

Department of Chemical and Biomolecular Engineering, Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD, USA.

Cells in vivo migrate in a complex microenvironment and are subjected to varying degrees of physical confinement provided by neighboring cells, tissues, and extracellular matrix. The molecular machinery that cells utilize to migrate through confining pores or microtracks shares both similarities and differences with that used in unconfined 2D migration. Depending on the exact properties of the local microenvironment and cell contractile state, cells can adopt distinct phenotypes and employ a wide array of mechanisms to migrate efficiently in confined spaces. Remarkably, these various migration modes are also interconvertible and interconnected, highlighting the plasticity and inherent complexity underlying confined cell migration. In this book chapter, an overview of the different molecular mechanisms utilized by cells to migrate in confinement is presented, with special emphasis on the extrinsic environmental and intrinsic molecular determinants that control the transformation from one mechanism to the other.
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http://dx.doi.org/10.1007/978-3-319-95294-9_8DOI Listing
July 2019

Vascular aging: Molecular mechanisms and potential treatments for vascular rejuvenation.

Ageing Res Rev 2017 Aug 1;37:94-116. Epub 2017 Jun 1.

Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Amherst, NY 14260-4200, USA; Department of Biomedical Engineering, University at Buffalo, The State University of New York, Amherst, NY 14260-4200, USA; Center of Excellence in Bioinformatics and Life Sciences, Buffalo, NY 14203, USA. Electronic address:

Aging is the main risk factor contributing to vascular dysfunction and the progression of vascular diseases. In this review, we discuss the causes and mechanisms of vascular aging at the tissue and cellular level. We focus on Endothelial Cell (EC) and Smooth Muscle Cell (SMC) aging due to their critical role in mediating the defective vascular phenotype. We elaborate on two categories that contribute to cellular dysfunction: cell extrinsic and intrinsic factors. Extrinsic factors reflect systemic or environmental changes which alter EC and SMC homeostasis compromising vascular function. Intrinsic factors induce EC and SMC transformation resulting in cellular senescence. Replenishing or rejuvenating the aged/dysfunctional vascular cells is critical to the effective repair of the vasculature. As such, this review also elaborates on recent findings which indicate that stem cell and gene therapies may restore the impaired vascular cell function, reverse vascular aging, and prolong lifespan.
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http://dx.doi.org/10.1016/j.arr.2017.05.006DOI Listing
August 2017

NANOG Restores Contractility of Mesenchymal Stem Cell-Based Senescent Microtissues.

Tissue Eng Part A 2017 06 28;23(11-12):535-545. Epub 2017 Feb 28.

1 Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York , Amherst, New York.

Mesenchymal stem cells (MSCs) have been extensively used in the field of tissue engineering as a source of smooth muscle cells (SMCs). However, recent studies showed deficits in the contractile function of SMCs derived from senescent MSCs and there are no available strategies to restore the contractile function that is impaired due to cellular or organismal senescence. In this study, we developed a tetracycline-regulatable system and employed micropost tissue arrays to evaluate the effects of the embryonic transcription factor, NANOG, on the contractility of senescent MSCs. Using this system, we show that expression of NANOG fortified the actin cytoskeleton and restored contractile function that was impaired in senescent MSCs. NANOG increased the expression of smooth muscle α-actin (ACTA2) as well as the contractile force generated by cells in three-dimensional microtissues. Interestingly, NANOG worked together with transforming growth factor-beta1 to further enhance the contractility of senescent microtissues. The effect of NANOG on contractile function was sustained for about 10 days after termination of its expression. Our results show that NANOG could reverse the effects of stem cell senescence and restore the myogenic differentiation potential of senescent MSCs. These findings may enable development of novel strategies to restore the function of senescent cardiovascular and other SMC-containing tissues.
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http://dx.doi.org/10.1089/ten.TEA.2016.0494DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5467120PMC
June 2017

Cancer cell motility: lessons from migration in confined spaces.

Nat Rev Cancer 2017 02 2;17(2):131-140. Epub 2016 Dec 2.

Department of Chemical and Biomolecular Engineering and the Institute for NanoBioTechnology, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.

Time-lapse, deep-tissue imaging made possible by advances in intravital microscopy has demonstrated the importance of tumour cell migration through confining tracks in vivo. These tracks may either be endogenous features of tissues or be created by tumour or tumour-associated cells. Importantly, migration mechanisms through confining microenvironments are not predicted by 2D migration assays. Engineered in vitro models have been used to delineate the mechanisms of cell motility through confining spaces encountered in vivo. Understanding cancer cell locomotion through physiologically relevant confining tracks could be useful in developing therapeutic strategies to combat metastasis.
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http://dx.doi.org/10.1038/nrc.2016.123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5364498PMC
February 2017

NANOG Reverses the Myogenic Differentiation Potential of Senescent Stem Cells by Restoring ACTIN Filamentous Organization and SRF-Dependent Gene Expression.

Stem Cells 2017 01 11;35(1):207-221. Epub 2016 Jul 11.

Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Amherst, New York, USA.

Cellular senescence as a result of organismal aging or progeroid diseases leads to stem cell pool exhaustion hindering tissue regeneration and contributing to the progression of age related disorders. Here we discovered that ectopic expression of the pluripotent factor NANOG in senescent or progeroid myogenic progenitors reversed cellular aging and restored completely the ability to generate contractile force. To elicit its effects, NANOG enabled reactivation of the ROCK and Transforming Growth Factor (TGF)-β pathways-both of which were impaired in senescent cells-leading to ACTIN polymerization, MRTF-A translocation into the nucleus and serum response factor (SRF)-dependent myogenic gene expression. Collectively our data reveal that cellular senescence can be reversed and provide a novel strategy to regain the lost function of aged stem cells without reprogramming to the pluripotent state. Stem Cells 2017;35:207-221.
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http://dx.doi.org/10.1002/stem.2452DOI Listing
January 2017

Lentiviral arrays for live-cell dynamic monitoring of gene and pathway activity during stem cell differentiation.

Mol Ther 2014 Nov 4;22(11):1971-82. Epub 2014 Jun 4.

1] Department of Chemical and Biological Engineering, Bioengineering Laboratory, University at Buffalo, The State University of New York, Amherst, New York, USA [2] Department of Biomedical Engineering, University at Buffalo, The State University of New York, New York, Amherst, USA [3] Center of Excellence in Bioinformatics and Life Sciences, Buffalo, New York, USA.

Uncovering the complexity of mesenchymal stem cell (MSC) differentiation requires novel methods to capture the dynamics of the process in a quantitative and high-throughput manner. To this end, we developed a lentiviral array (LVA) of reporters to capture the dynamics of gene and pathway activity during MSC differentiation into adipogenic, chondrogenic, and osteogenic lineages. Our results identified signature promoters and pathways with unique activation profile for each MSC lineage. In combination with chemical inhibitors, lineage-specific reporters predicted the effects of signaling pathway perturbations on MSC differentiation. Interestingly, some pathways were critical for differentiation into all lineages, while others had differential effects on each lineage. Our study suggests that when combined with large chemical or siRNA libraries, the reporter LVA can be used to uncover novel genes and signaling pathways affecting complex biological processes such as stem cell differentiation or reprogramming.
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http://dx.doi.org/10.1038/mt.2014.103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429726PMC
November 2014

Poly(ethylene glycol)-block-cationic polylactide nanocomplexes of differing charge density for gene delivery.

Biomaterials 2013 Dec 10;34(37):9688-99. Epub 2013 Sep 10.

Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Amherst, NY 14260, USA.

Representing a new type of biodegradable cationic block copolymer, well-defined poly(ethylene glycol)-block-cationic polylactides (PEG-b-CPLAs) with tertiary amine-based cationic groups were synthesized by thiol-ene functionalization of an allyl-functionalized diblock precursor. Subsequently the application of PEG-b-CPLAs as biodegradable vectors for the delivery of plasmid DNAs (pDNAs) was investigated. Via the formation of PEG-b-CPLA:pDNA nanocomplexes by spontaneous electrostatic interaction, pDNAs encoding luciferase or enhanced green fluorescent protein were successfully delivered to four physiologically distinct cell lines (including macrophage, fibroblast, epithelial, and stem cell). Formulated nanocomplexes demonstrated high levels of transfection with low levels of cytotoxicity and hemolysis when compared to a positive control. Biophysical characterization of charge densities of nanocomplexes at various polymer:pDNA weight ratios revealed a positive correlation between surface charge and gene delivery. Nanocomplexes with high surface charge densities were utilized in an in vitro serum gene delivery inhibition assay, and effective gene delivery was observed despite high levels of serum. Overall, these results help to elucidate the influence of charge, size, and PEGylation of nanocomplexes upon the delivery of nucleic acids in physiologically relevant conditions.
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http://dx.doi.org/10.1016/j.biomaterials.2013.08.063DOI Listing
December 2013

Hair follicle: a novel source of multipotent stem cells for tissue engineering and regenerative medicine.

Tissue Eng Part B Rev 2013 Aug 3;19(4):265-78. Epub 2013 Jan 3.

Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Amherst, New York 14260-4200, USA.

The adult body harbors powerful reservoirs of stem cells that enable tissue regeneration under homeostatic conditions or in response to disease or injury. The hair follicle (HF) is a readily accessible mini organ within the skin and contains stem cells from diverse developmental origins that were shown to have surprisingly broad differentiation potential. In this review, we discuss the biology of the HF with particular emphasis on the various stem cell populations residing within the tissue. We summarize the existing knowledge on putative HF stem cell markers, the differentiation potential, and technologies to isolate and expand distinct stem cell populations. We also discuss the potential of HF stem cells for drug and gene delivery, tissue engineering, and regenerative medicine. We propose that the abundance of stem cells with broad differentiation potential and the ease of accessibility makes the HF an ideal source of stem cells for gene and cell therapies.
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http://dx.doi.org/10.1089/ten.TEB.2012.0422DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3690091PMC
August 2013

Nanog reverses the effects of organismal aging on mesenchymal stem cell proliferation and myogenic differentiation potential.

Stem Cells 2012 Dec;30(12):2746-59

Department of Chemical and Biological Engineering, University at Buffalo, State University of New York, Amherst, New York 14260-4200, USA.

Although the therapeutic potential of mesenchymal stem cells (MSCs) is widely accepted, loss of cell function due to donor aging or culture senescence are major limiting factors hampering their clinical application. Our laboratory recently showed that MSCs originating from older donors suffer from limited proliferative capacity and significantly reduced myogenic differentiation potential. This is a major concern, as the patients most likely to suffer from cardiovascular disease are elderly. Here we tested the hypothesis that a single pluripotency-associated transcription factor, namely Nanog, may reverse the proliferation and differentiation potential of bone marrow-derived MSC (BM-MSC) from adult donors. Microarray analysis showed that adult (a)BM-MSC expressing Nanog clustered close to Nanog-expressing neonatal cells. Nanog markedly upregulated genes involved in cell cycle, DNA replication, and DNA damage repair and enhanced the proliferation rate and clonogenic capacity of aBM-MSC. Notably, Nanog reversed the myogenic differentiation potential and restored the contractile function of aBM-MSC to a similar level as that of neonatal (n)BM-MSC. The effect of Nanog on contractility was mediated--at least in part--through activation of the TGF-β pathway by diffusible factors secreted in the conditioned medium of Nanog-expressing BM-MSC. Overall, our results suggest that Nanog may be used to overcome the effects of organismal aging on aBM-MSC, thereby increasing the potential of MSC from aged donors for cellular therapy and tissue regeneration.
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http://dx.doi.org/10.1002/stem.1223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3508087PMC
December 2012

Functional vascular smooth muscle cells derived from human induced pluripotent stem cells via mesenchymal stem cell intermediates.

Cardiovasc Res 2012 Dec 31;96(3):391-400. Epub 2012 Aug 31.

Bioengineering Laboratory, Department of Chemical and Biological Engineering, University of Buffalo, The State University of New York, 908 Furnas Hall, Amherst, NY 14260-4200, USA.

Aims: Smooth muscle cells (SMC) play an important role in vascular homeostasis and disease. Although adult mesenchymal stem cells (MSC) have been used as a source of contractile SMC, they suffer from limited proliferation potential and culture senescence, particularly when originating from older donors. By comparison, human induced pluripotent stem cells (hiPSC) can provide an unlimited source of functional SMC for autologous cell-based therapies and for creating models of vascular disease. Our goal was to develop an efficient strategy to derive functional, contractile SMC from hiPSC.

Methods And Results: We developed a robust, stage-wise, feeder-free strategy for hiPSC differentiation into functional SMC through an intermediate stage of multipotent MSC, which could be coaxed to differentiate into fat, bone, cartilage, and muscle. At this stage, the cells were highly proliferative and displayed higher clonogenic potential and reduced senescence when compared with parental hair follicle mesenchymal stem cells. In addition, when exposed to differentiation medium, the myogenic proteins such as α-smooth muscle actin, calponin, and myosin heavy chain were significantly upregulated and displayed robust fibrillar organization, suggesting the development of a contractile phenotype. Indeed, tissue constructs prepared from these cells exhibited high levels of contractility in response to receptor- and non-receptor-mediated agonists.

Conclusion: We developed an efficient stage-wise strategy that enabled hiPSC differentiation into contractile SMC through an intermediate population of clonogenic and multipotent MSC. The high yield of MSC and SMC derivation suggests that our strategy may facilitate an acquisition of the large numbers of cells required for regenerative medicine or for studying vascular disease pathophysiology.
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http://dx.doi.org/10.1093/cvr/cvs253DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3584971PMC
December 2012

Clonal multipotency and effect of long-term in vitro expansion on differentiation potential of human hair follicle derived mesenchymal stem cells.

Stem Cell Res 2012 Jan 9;8(1):74-84. Epub 2011 Aug 9.

Bioengineering Laboratory, Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Amherst, NY 14260-4200, USA.

Hair follicle harbors a rich stem cell pool with mesenchymal lineage differentiation potential. Although previous studies with rodent cells demonstrated that hair follicle sheath and papilla cells possess multi-lineage differentiation potential, human hair follicle derived mesenchymal stem cells (hHF-MSCs) have not been characterized in detail in terms of their multipotency. In addition, it is not clear whether these cells are true stem cells that can differentiate along multiple lineages or whether they represent a collection of progenitor cells with restricted differentiation potential. Here we report that hHF-MSCs are highly proliferative cells that can be maintained in culture for ~45 population doublings before they start to show signs of cellular senescence. Under appropriate culture conditions, hHF-MSCs differentiated along the myogenic, osteogenic, adipogenic and chondrogenic lineages, as demonstrated by kinetic gene expression profiling and functional assays. Interestingly, the differentiation potential decreased with time in culture in a lineage-specific manner. Specifically, myogenesis and chondrogenesis showed a moderate decrease over time; osteogenesis was maximum at intermediate passages and adipogenesis was highly sensitive to long-term culture and was diminished at late passages. Finally, hHF-MSCs were clonally multipotent as the majority of hHF-MSCs clones (73%) demonstrated bi- or tri-lineage differentiation potential. These results suggest that hHF-MSCs may present as an alternative source of easily accessible, autologous stem cells for tissue engineering and regenerative medicine.
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http://dx.doi.org/10.1016/j.scr.2011.07.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222855PMC
January 2012
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