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Kodali M, Madhu LN, Reger RL, Milutinovic B, Upadhya R, Attaluri S, Shuai B, Shankar G, Shetty AK. A single intranasal dose of human mesenchymal stem cell-derived extracellular vesicles after traumatic brain injury eases neurogenesis decline, synapse loss, and BDNF-ERK-CREB signaling. Front Mol Neurosci 2023; 16:1185883. [PMID: 37284464 PMCID: PMC10239975 DOI: 10.3389/fnmol.2023.1185883] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 04/28/2023] [Indexed: 06/08/2023] Open
Abstract
An optimal intranasal (IN) dose of human mesenchymal stem cell-derived extracellular vesicles (hMSC-EVs), 90 min post-traumatic brain injury (TBI), has been reported to prevent the evolution of acute neuroinflammation into chronic neuroinflammation resulting in the alleviation of long-term cognitive and mood impairments. Since hippocampal neurogenesis decline and synapse loss contribute to TBI-induced long-term cognitive and mood dysfunction, this study investigated whether hMSC-EV treatment after TBI can prevent hippocampal neurogenesis decline and synapse loss in the chronic phase of TBI. C57BL6 mice undergoing unilateral controlled cortical impact injury (CCI) received a single IN administration of different doses of EVs or the vehicle at 90 min post-TBI. Quantifying neurogenesis in the subgranular zone-granule cell layer (SGZ-GCL) through 5'-bromodeoxyuridine and neuron-specific nuclear antigen double labeling at ~2 months post-TBI revealed decreased neurogenesis in TBI mice receiving vehicle. However, in TBI mice receiving EVs (12.8 and 25.6 × 109 EVs), the extent of neurogenesis was matched to naive control levels. A similar trend of decreased neurogenesis was seen when doublecortin-positive newly generated neurons were quantified in the SGZ-GCL at ~3 months post-TBI. The above doses of EVs treatment after TBI also reduced the loss of pre-and post-synaptic marker proteins in the hippocampus and the somatosensory cortex. Moreover, at 48 h post-treatment, brain-derived neurotrophic factor (BDNF), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), and phosphorylated cyclic AMP response-element binding protein (p-CREB) levels were downregulated in TBI mice receiving the vehicle but were closer to naïve control levels in TBI mice receiving above doses of hMSC-EVs. Notably, improved BDNF concentration observed in TBI mice receiving hMSC-EVs in the acute phase was sustained in the chronic phase of TBI. Thus, a single IN dose of hMSC-EVs at 90 min post-TBI can ease TBI-induced declines in the BDNF-ERK-CREB signaling, hippocampal neurogenesis, and synapses.
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Kodali M, Madhu LN, Reger RL, Milutinovic B, Upadhya R, Gonzalez JJ, Attaluri S, Shuai B, Gitai DLG, Rao S, Choi JM, Jung SY, Shetty AK. Intranasally administered human MSC-derived extracellular vesicles inhibit NLRP3-p38/MAPK signaling after TBI and prevent chronic brain dysfunction. Brain Behav Immun 2023; 108:118-134. [PMID: 36427808 PMCID: PMC9974012 DOI: 10.1016/j.bbi.2022.11.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 10/21/2022] [Accepted: 11/19/2022] [Indexed: 11/25/2022] Open
Abstract
Traumatic brain injury (TBI) leads to lasting brain dysfunction with chronic neuroinflammation typified by nucleotide-binding domain leucine-rich repeat and pyrin domain-containing receptor 3 (NLRP3) inflammasome activation in microglia. This study probed whether a single intranasal (IN) administration of human mesenchymal stem cell-derived extracellular vesicles (hMSC-EVs) naturally enriched with activated microglia-modulating miRNAs can avert chronic adverse outcomes of TBI. Small RNA sequencing confirmed the enrichment of miRNAs capable of modulating activated microglia in hMSC-EV cargo. IN administration of hMSC-EVs into adult mice ninety minutes after the induction of a unilateral controlled cortical impact injury resulted in their incorporation into neurons and microglia in both injured and contralateral hemispheres. A single higher dose hMSC-EV treatment also inhibited NLRP3 inflammasome activation after TBI, evidenced by reduced NLRP3, apoptosis-associated speck-like protein containing a CARD, activated caspase-1, interleukin-1 beta, and IL-18 levels in the injured brain. Such inhibition in the acute phase of TBI endured in the chronic phase, which could also be gleaned from diminished NLRP3 inflammasome activation in microglia of TBI mice receiving hMSC-EVs. Proteomic analysis and validation revealed that higher dose hMSC-EV treatment thwarted the chronic activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway by IL-18, which decreased the release of proinflammatory cytokines. Inhibition of the chronic activation of NLRP3-p38/MAPK signaling after TBI also prevented long-term cognitive and mood impairments. Notably, the animals receiving higher doses of hMSC-EVs after TBI displayed better cognitive and mood function in all behavioral tests than animals receiving the vehicle after TBI. A lower dose of hMSC-EV treatment also partially improved cognitive and mood function. Thus, an optimal IN dose of hMSC-EVs naturally enriched with activated microglia-modulating miRNAs can inhibit the chronic activation of NLRP3-p38/MAPK signaling after TBI and prevent lasting brain dysfunction.
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Affiliation(s)
- Maheedhar Kodali
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Leelavathi N Madhu
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Roxanne L Reger
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Bojana Milutinovic
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Raghavendra Upadhya
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Jenny J Gonzalez
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Sahithi Attaluri
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Bing Shuai
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Daniel L G Gitai
- Institute of Biological Sciences and Health, Federal University of Alagoas, Brazil
| | - Shama Rao
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA
| | - Jong M Choi
- Advanced Technology Core, Mass Spectrometry and Proteomics Core, Baylor College of Medicine, Houston, TX, USA
| | - Sung Y Jung
- The Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Ashok K Shetty
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA.
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Choi H, Phillips C, Oh JY, Potts L, Reger RL, Prockop DJ, Fulcher S. Absence of Therapeutic Benefit of the Anti-Inflammatory Protein TSG-6 for Corneal Alkali Injury in a Rat Model. Curr Eye Res 2019; 44:873-881. [PMID: 30935217 DOI: 10.1080/02713683.2019.1597893] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Purpose: To investigate the therapeutic efficacy of tumor necrosis factor (TNF)-α stimulated gene/protein 6 (TSG-6) in a rat model of corneal alkali injury. Methods: Corneal alkali injury was produced by placing an NaOH-soaked filter paper disk on the central cornea of the right eye of an anesthetized male Lewis (LEW/Crl) rat. Recombinant human TSG-6, or an equal volume of phosphate-buffered saline (PBS), was administered intravenously (IV), by anterior chamber (AC) injection, or as a topical drop. The affected eyes were photographed daily using a dissecting microscope and documented for clinical time course analysis of corneal opacification. Corneal tissue was excised at pre-determined therapeutic endpoints, with subsequent qRT-PCR or histological analyses. Results: The continuous monitoring of corneal alkali injury progression revealed TSG-6 treatments do not show sufficient effectiveness in vivo regardless of IV injection, AC injection, or topical application. Corneal opacification and neovascularization were not diminished, and gene expression was not impacted by these treatments. However, both IV and AC administration of TSG-6 significantly suppressed pro-inflammatory cytokines compared to PBS-treated eyes. Conclusion: We conclude that the therapeutic potential of TSG-6 is insufficient in a rat corneal alkali injury model.
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Affiliation(s)
- Hosoon Choi
- a Department of Basic Research, Central Texas Veterans Research Foundation , Temple , Texas , USA
| | - Casie Phillips
- a Department of Basic Research, Central Texas Veterans Research Foundation , Temple , Texas , USA
| | - Joo Youn Oh
- b Department of Ophthalmology, Seoul National University Hospital , Seoul , Republic of Korea
| | - Luke Potts
- c Department of Ophthalmology and Surgery, Scott and White Eye Institute , Temple , Texas , USA
| | - Roxanne L Reger
- d Institute for Regenerative Medicine, College of Medicine, Texas A&M University , College Station , Texas , USA
| | - Darwin J Prockop
- d Institute for Regenerative Medicine, College of Medicine, Texas A&M University , College Station , Texas , USA
| | - Samuel Fulcher
- e Department of Surgery, Central Texas Veterans Health Care System , Temple , Texas , United States of America
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Yun YI, Park SY, Lee HJ, Ko JH, Kim MK, Wee WR, Reger RL, Gregory CA, Choi H, Fulcher SF, Prockop DJ, Oh JY. Comparison of the anti-inflammatory effects of induced pluripotent stem cell–derived and bone marrow–derived mesenchymal stromal cells in a murine model of corneal injury. Cytotherapy 2017; 19:28-35. [DOI: 10.1016/j.jcyt.2016.10.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/27/2016] [Accepted: 10/17/2016] [Indexed: 12/24/2022]
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Abstract
There has been great interest in research and clinical trials with the adult stem/progenitor cells referred to as mesenchymal stem/stromal cells (MSCs). However, there are no definitive markers for the cells and no assays that would reflect the therapeutic efficacy of the cells in vivo. There are in effect no adequate release criteria that define the quality or efficacy of the cells. The problems are compounded by the fact that a variety of different protocols has been used to isolate the cells and expand them in culture. The result is that many publications have used MSCs with different properties, frequently without the investigators being aware of the differences. As a partial solution to these problems, we have devised a simple table to record in-process data on the preparation of MSCs. We suggest that comparisons of data generated by different laboratories would be facilitated if similar in-process data, probably as supplemental materials, were included in publications using MSCs.
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Affiliation(s)
- Roxanne L Reger
- Institute for Regenerative Medicine, Texas A&M Health Science Center College of Medicine, Temple, Texas, USA
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Abstract
In this review, we focus on the adult stem/progenitor cells that were initially isolated from bone marrow and first referred to as colony forming units-fibroblastic, then as marrow stromal cells and subsequently as either mesenchymal stem cells or multipotent mesenchymal stromal cells (MSCs). The current interest in MSCs and similar cells from other tissues is reflected in over 10,000 citations in PubMed at the time of this writing with 5 to 10 new publications per day. It is also reflected in over 100 registered clinical trials with MSCs or related cells (http//www.clinicaltrials.gov). As a guide to the vast literature, this review will attempt to summarize many of the publications in terms of three paradigms that have directed much of the work: an initial paradigm that the primary role of the cells was to form niches for haematopoietic stem cells (paradigm I); a second paradigm that the cells repaired tissues by engraftment and differentiation to replace injured cells (paradigm II); and the more recent paradigm that MSCs engage in cross-talk with injured tissues and thereby generate microenvironments or ‘quasi-niches’ that enhance the repair tissues (paradigm III).
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Affiliation(s)
- Darwin J Prockop
- Texas A & M Health Science Center College of Medicine Institute for Regenerative Medicine at Scott & White, Temple, TX 76502, USA.
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7
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Abstract
In this review, we focus on the adult stem/progenitor cells that were initially isolated from bone marrow and first referred to as colony forming units-fibroblastic, then as marrow stromal cells and subsequently as either mesenchymal stem cells or multipotent mesenchymal stromal cells (MSCs). The current interest in MSCs and similar cells from other tissues is reflected in over 10,000 citations in PubMed at the time of this writing with 5 to 10 new publications per day. It is also reflected in over 100 registered clinical trials with MSCs or related cells (http//www.clinicaltrials.gov). As a guide to the vast literature, this review will attempt to summarize many of the publications in terms of three paradigms that have directed much of the work: an initial paradigm that the primary role of the cells was to form niches for haematopoietic stem cells (paradigm I); a second paradigm that the cells repaired tissues by engraftment and differentiation to replace injured cells (paradigm II); and the more recent paradigm that MSCs engage in cross-talk with injured tissues and thereby generate microenvironments or 'quasi-niches' that enhance the repair tissues (paradigm III).
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Affiliation(s)
- Darwin J Prockop
- Texas A & M Health Science Center College of Medicine Institute for Regenerative Medicine at Scott & White, Temple, TX 76502, USA.
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Reger RL, Wolfe MR. Freezing harvested hMSCs and recovery of hMSCs from frozen vials for subsequent expansion, analysis, and experimentation. Methods Mol Biol 2008; 449:109-16. [PMID: 18370087 DOI: 10.1007/978-1-60327-169-1_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Human multipotential stromal cells (hMSCs) are easily isolated from bone marrow and can be expanded by up to 200-fold in culture. Cultures of hMSCs are heterogeneous mixtures of stem/progenitor cells and more mature cell types. The proportion of each cell type in a given culture depends on how the cells are maintained. To maintain their stem cell-like qualities, hMSCs should be plated at low seeding densities (60-150 cells/cm2), lifted when between 60% and 80% confluent and should not be expanded beyond 4-5 passages. Thus, it is useful to establish a frozen bank of early passage cells. hMSCs store well in vapor phase liquid nitrogen (LN2) and are easily recovered for further expansion. This chapter describes one method of establishing a bank of early passage hMSCs using a seed lot system and the subsequent recovery of hMSCs from frozen stocks. The recovered cells can then be harvested and used for analyses of identification, functionality, in vitro and/or in vivo experimentation, or further expanded.
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Affiliation(s)
- Roxanne L Reger
- Center for Gene Therapy, Tulane University Health Sciences Center, New Orleans, LA, USA
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Abstract
We have developed protocols whereby a total of 30-90 x 10(6) hMSCs with an average viability greater than 90% can be produced in a single multilevel Cell Factory from a relatively small (1-3 mL) bone marrow aspirate in 14-20 d. It is possible to generate as many as 5 x 10(8) multipotent stromal cells (MSCs) from a single sample, depending on the number of Cell Factories seeded from the initial isolated hMSCs. Briefly, mononuclear cells are collected from a bone marrow aspirate by density gradient centrifugation. The cells are cultured overnight and the adherent cells are allowed to attach to the flask. Nonadherent cells are removed and the culture expanded for 7-10 d with periodic feeding of the cells. The cells are then harvested and seeded at low density (60-100 cells/cm2) into Nunc Cell Factories. The cells are allowed to expand for an additional 7-10 d, and are then harvested.
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Affiliation(s)
- Margaret Wolfe
- Center for Gene Therapy, Tulane University Health Sciences Center, New Orleans, LA, USA
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Lee RH, Seo MJ, Reger RL, Spees JL, Pulin AA, Olson SD, Prockop DJ. Multipotent stromal cells from human marrow home to and promote repair of pancreatic islets and renal glomeruli in diabetic NOD/scid mice. Proc Natl Acad Sci U S A 2006; 103:17438-43. [PMID: 17088535 PMCID: PMC1634835 DOI: 10.1073/pnas.0608249103] [Citation(s) in RCA: 532] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We tested the hypothesis that multipotent stromal cells from human bone marrow (hMSCs) can provide a potential therapy for human diabetes mellitus. Severe but nonlethal hyperglycemia was produced in NOD/scid mice with daily low doses of streptozotocin on days 1-4, and hMSCs were delivered via intracardiac infusion on days 10 and 17. The hMSCs lowered blood glucose levels in the diabetic mice on day 32 relative to untreated controls (18.34 mM +/- 1.12 SE vs. 27.78 mM +/- 2.45 SE, P = 0.0019). ELISAs demonstrated that blood levels of mouse insulin were higher in the hMSC-treated as compared with untreated diabetic mice, but human insulin was not detected. PCR assays detected human Alu sequences in DNA in pancreas and kidney on day 17 or 32 but not in other tissues, except heart, into which the cells were infused. In the hMSC-treated diabetic mice, there was an increase in pancreatic islets and beta cells producing mouse insulin. Rare islets contained human cells that colabeled for human insulin or PDX-1. Most of the beta cells in the islets were mouse cells that expressed mouse insulin. In kidneys of hMSC-treated diabetic mice, human cells were found in the glomeruli. There was a decrease in mesangial thickening and a decrease in macrophage infiltration. A few of the human cells appeared to differentiate into glomerular endothelial cells. Therefore, the results raised the possibility that hMSCs may be useful in enhancing insulin secretion and perhaps improving the renal lesions that develop in patients with diabetes mellitus.
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Affiliation(s)
- Ryang Hwa Lee
- *Center for Gene Therapy, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112; and
| | - Min Jeong Seo
- *Center for Gene Therapy, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112; and
| | - Roxanne L. Reger
- *Center for Gene Therapy, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112; and
| | - Jeffrey L. Spees
- *Center for Gene Therapy, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112; and
- Department of Medicine, Cardiovascular Research Institute, University of Vermont, 208 South Park Drive, Suite 2, Colchester, VT 05446
| | - Andrey A. Pulin
- *Center for Gene Therapy, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112; and
| | - Scott D. Olson
- *Center for Gene Therapy, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112; and
| | - Darwin J. Prockop
- *Center for Gene Therapy, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112; and
- To whom correspondence should be addressed. E-mail:
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Peister A, Zeitouni S, Pfankuch T, Reger RL, Prockop DJ, Raber J. Novel object recognition in Apoe−/− mice improved by neonatal implantation of wild-type multipotential stromal cells. Exp Neurol 2006; 201:266-9. [PMID: 16808914 DOI: 10.1016/j.expneurol.2006.03.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 03/29/2006] [Accepted: 03/31/2006] [Indexed: 11/20/2022]
Abstract
Multipotential bone marrow stromal cells (MSCs) from wild-type (Wt) or apolipoprotein E deficient (Apoe(-/-)) mice were implanted into the cerebral ventricles of Apoe(-/-) mice. MSCs from Wt mice continued expressing apoE up to 6 months after implantation and were associated with enhanced novel object recognition and increased microtubule-associated protein 2 (MAP2) immunoreactivity in the dentate gyrus. These data show that MSCs can be used to distinguish developmental from post-developmental effects of a gene knockout and support their therapeutic potential for neurodegenerative diseases.
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Affiliation(s)
- Alexandra Peister
- Center for Gene Therapy, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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Sekiya I, Larson BL, Vuoristo JT, Reger RL, Prockop DJ. Comparison of effect of BMP-2, -4, and -6 on in vitro cartilage formation of human adult stem cells from bone marrow stroma. Cell Tissue Res 2005; 320:269-76. [PMID: 15778851 DOI: 10.1007/s00441-004-1075-3] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Accepted: 12/15/2004] [Indexed: 12/13/2022]
Abstract
The human adult stem cells from bone marrow stroma referred to as mesenchymal stem cells or marrow stromal cells (MSCs) are of interest because they are easily isolated and expanded and are capable of multipotential differentiation. Here, we examined the ability of recombinant human bone morphogenetic protein (BMP)-2, -4, and -6 to enhance in vitro cartilage formation of MSCs. Human MSCs were isolated from bone marrow taken from normal adult donors. The cells were pelleted and cultured for 21 days in chondrogenic medium containing transforming growth factor beta3 and dexamethasone with or without BMP-2, -4, or -6. All the BMPs tested increased chondrogenic differentiation as assayed by immunohistochemistry and by the size and weight of the cartilage synthesized. However, BMP-2 was the most effective. Microarray analyses of approximately 12,000 genes and reverse transcription-polymerase chain reaction assays established that the critical genes for cartilage synthesis were expressed in the expected time sequence in response to BMP-2. The tissue engineering of autologous cartilage derived from MSCs in vitro for transplantation will be a future alternative for patients with cartilage injuries. To obtain large amounts of cartilage rich in proteoglycans, the use of BMP-2 is recommended, instead of BMP-4 or -6.
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Affiliation(s)
- Ichiro Sekiya
- Center for Gene Therapy, Tulane University Health Sciences Center, New Orleans, LA 70112-2699, USA
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Awayda MS, Platzer JD, Reger RL, Bengrine A. Role of PKCalpha in feedback regulation of Na(+) transport in an electrically tight epithelium. Am J Physiol Cell Physiol 2002; 283:C1122-32. [PMID: 12225976 DOI: 10.1152/ajpcell.00142.2002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It has long been known that Na(+) channels in electrically tight epithelia are regulated by homeostatic mechanisms that maintain a steady state and allow new levels of transport to be sustained in hormonally challenged cells. Little is known about the potential pathways involved in these processes. In addition to short-term effect, recent evidence also indicates the involvement of PKC in the long-term regulation of the epithelial Na(+) channel (ENaC) at the protein level (40). To determine whether stimulation of ENaC involves feedback regulation of PKC levels, we utilized Western blot analysis to determine the distribution of PKC isoforms in polarized A6 epithelia. We found the presence of PKC isoforms in the conventional (alpha and gamma), novel (delta, eta, and epsilon), and atypical (iota, lambda, and zeta) groups. Steady-state stimulation of Na(+) transport with aldosterone was accompanied by a specific decrease of PKCalpha protein levels in both the cytoplasmic and membrane fractions. Similarly, overnight treatment with an uncharged amiloride analog (CDPC), a procedure that through feedback regulation causes a stimulation of Na(+) transport, also decreased PKCalpha levels. These effects were additive, indicating separate mechanisms that converge at the level of PKCalpha. These effects were not accompanied by changes of PKCalpha mRNA levels as determined by Northern blot analysis. We propose that this may represent a novel regulatory feedback mechanism necessary for sustaining an increase of Na(+) transport.
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Affiliation(s)
- Mouhamed S Awayda
- Department of Physiology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.
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Schwarz EJ, Reger RL, Alexander GM, Class R, Azizi SA, Prockop DJ. Rat marrow stromal cells rapidly transduced with a self-inactivating retrovirus synthesize L-DOPA in vitro. Gene Ther 2001; 8:1214-23. [PMID: 11509954 DOI: 10.1038/sj.gt.3301517] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2000] [Accepted: 05/22/2001] [Indexed: 01/14/2023]
Abstract
Autologous bone marrow stromal cells engineered to produce 3,4,-dihydroxyphenylalanine (L-DOPA) can potentially be used as donor cells for neural transplantation in Parkinson's disease. Here, we examined the possibility of using several different promoters and either a self-inactivating retrovirus (pSIR) or standard retroviruses to introduce into marrow stromal cells (MSCs), the two genes necessary for the cells to synthesize L-DOPA. pSIR vectors were constructed using the mouse phosphoglycerate kinase-1 (PGK) promoter or the cytomegalovirus (CMV) promoter to drive expression of either a GFP reporter gene or a bicistronic sequence containing the genes for human tyrosine hydroxylase type I (TH) and rat GTP cyclohydrolase I (GC) separated by an internal ribosome entry site (IRES). rMSCs were successfully transduced with both standard retroviral vectors and pSIR containing the PGK promoter. Transduced rMSCs expressed GFP (90.4--94.4% of cells) or were able to synthesize and secrete L-DOPA (89.0--283 pmols/10(6) cells/h). After transduced rMSCs were plated at low density (3--6 cells/cm(2)), the cells expanded over 1000-fold in 3--4 weeks, and the rMSCs continued to either express GFP or produce L-DOPA. Furthermore, two high-expressing clones were isolated and expanded at low-density from rMSCs transduced with pSIR driven by the PGK promoter (97.0% GFP+ or 1096.0 pmols L-DOPA/10(6) cells/h).
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Affiliation(s)
- E J Schwarz
- Center for Gene Therapy, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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15
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Abstract
The effect of extracellular acidification was tested on the native epithelial Na(+) channel (ENaC) in A6 epithelia and on the cloned ENaC expressed in Xenopus oocytes. Channel activity was determined utilizing blocker-induced fluctuation analysis in A6 epithelia and dual electrode voltage clamp in oocytes. In A6 cells, a decrease of extracellular pH (pH(o)) from 7.4 to 6.4 caused a slow stimulation of the amiloride-sensitive short-circuit current (I(Na)) by 68.4 +/- 11% (n = 9) at 60 min. This increase of I(Na) was attributed to an increase of open channel and total channel (N(T)) densities. Similar changes were observed with pH(o) 5.4. The effects of pH(o) were blocked by buffering intracellular Ca(2+) with 5 microM 1, 2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. In oocytes, pH(o) 6.4 elicited a small transient increase of the slope conductance of the cloned ENaC (11.4 +/- 2.2% at 2 min) followed by a decrease to 83.7 +/- 11.7% of control at 60 min (n = 6). Thus small decreases of pH(o) stimulate the native ENaC by increasing N(T) but do not appreciably affect ENaC expressed in Xenopus oocytes. These effects are distinct from those observed with decreasing intracellular pH with permeant buffers that are known to inhibit ENaC.
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Affiliation(s)
- M S Awayda
- Departments of Medicine and of Physiology, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA.
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