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Myint M, Oppedisano F, De Giorgi V, Kim BM, Marincola FM, Alter HJ, Nesci S. Inflammatory signaling in NASH driven by hepatocyte mitochondrial dysfunctions. J Transl Med 2023; 21:757. [PMID: 37884933 PMCID: PMC10605416 DOI: 10.1186/s12967-023-04627-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 10/14/2023] [Indexed: 10/28/2023] Open
Abstract
Liver steatosis, inflammation, and variable degrees of fibrosis are the pathological manifestations of nonalcoholic steatohepatitis (NASH), an aggressive presentation of the most prevalent chronic liver disease in the Western world known as nonalcoholic fatty liver (NAFL). Mitochondrial hepatocyte dysfunction is a primary event that triggers inflammation, affecting Kupffer and hepatic stellate cell behaviour. Here, we consider the role of impaired mitochondrial function caused by lipotoxicity during oxidative stress in hepatocytes. Dysfunction in oxidative phosphorylation and mitochondrial ROS production cause the release of damage-associated molecular patterns from dying hepatocytes, leading to activation of innate immunity and trans-differentiation of hepatic stellate cells, thereby driving fibrosis in NASH.
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Affiliation(s)
| | - Francesca Oppedisano
- Department of Health Sciences, Institute of Research for Food Safety and Health, University "Magna Græcia" of Catanzaro, Catanzaro, Italy
| | - Valeria De Giorgi
- Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, USA
| | | | | | - Harvey J Alter
- Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, USA
| | - Salvatore Nesci
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, Italy.
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Galluzzi L, Myint M. Cell death and senescence. J Transl Med 2023; 21:425. [PMID: 37386590 DOI: 10.1186/s12967-023-04297-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023] Open
Affiliation(s)
- Lorenzo Galluzzi
- Department of Radiation Oncology, Weill Cornell Medical College, New York, NY, USA.
- Sandra and Edward Meyer Cancer Center, New York, NY, USA.
- Caryl and Israel Englander Institute for Precision Medicine, New York, NY, USA.
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Blagovic K, Smith CK, Ramakrishnan A, Moore L, Soto DR, Thompson Z, Stockmann AP, Kruszelnicki S, Thakkar A, Murray J, Torres S, Wondimagegnhu B, Yi R, Dadgar M, Paracha AM, Page C, Clear L, Chaudhry OA, Myint M, Bridgen DT, Gilbert JB, Seidl KJ, Sharei A, Loughhead S, Bernstein H, Yarar D. Engineered red blood cells (activating antigen carriers) drive potent T cell responses and tumor regression in mice. Front Immunol 2022; 13:1015585. [PMID: 36263022 PMCID: PMC9573954 DOI: 10.3389/fimmu.2022.1015585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 09/14/2022] [Indexed: 11/22/2022] Open
Abstract
Activation of T cell responses is essential for effective tumor clearance; however, inducing targeted, potent antigen presentation to stimulate T cell responses remains challenging. We generated Activating Antigen Carriers (AACs) by engineering red blood cells (RBCs) to encapsulate relevant tumor antigens and the adjuvant polyinosinic-polycytidylic acid (poly I:C), for use as a tumor-specific cancer vaccine. The processing method and conditions used to create the AACs promote phosphatidylserine exposure on RBCs and thus harness the natural process of aged RBC clearance to enable targeting of the AACs to endogenous professional antigen presenting cells (APCs) without the use of chemicals or viral vectors. AAC uptake, antigen processing, and presentation by APCs drive antigen-specific activation of T cells, both in mouse in vivo and human in vitro systems, promoting polyfunctionality of CD8+ T cells and, in a tumor model, driving high levels of antigen-specific CD8+ T cell infiltration and tumor killing. The efficacy of AAC therapy was further enhanced by combination with the chemotherapeutic agent Cisplatin. In summary, these findings support AACs as a potential vector-free immunotherapy strategy to enable potent antigen presentation and T cell stimulation by endogenous APCs with broad therapeutic potential.
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Booty MG, Hlavaty KA, Stockmann A, Ozay EI, Smith C, Tian L, How E, Subramanya D, Venkitaraman A, Yee C, Pryor O, Volk K, Blagovic K, Vicente-Suarez I, Yarar D, Myint M, Merino A, Chow J, Abdeljawad T, An H, Liu S, Mao S, Heimann M, Talarico L, Jacques MK, Chong E, Pomerance L, Gonzalez JT, von Andrian UH, Jensen KF, Langer R, Knoetgen H, Trumpfheller C, Umaña P, Bernstein H, Sharei A, Loughhead SM. Microfluidic Squeezing Enables MHC Class I Antigen Presentation by Diverse Immune Cells to Elicit CD8 + T Cell Responses with Antitumor Activity. J Immunol 2022; 208:929-940. [PMID: 35091434 DOI: 10.4049/jimmunol.2100656] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 12/07/2021] [Indexed: 12/30/2022]
Abstract
CD8+ T cell responses are the foundation of the recent clinical success of immunotherapy in oncologic indications. Although checkpoint inhibitors have enhanced the activity of existing CD8+ T cell responses, therapeutic approaches to generate Ag-specific CD8+ T cell responses have had limited success. Here, we demonstrate that cytosolic delivery of Ag through microfluidic squeezing enables MHC class I presentation to CD8+ T cells by diverse cell types. In murine dendritic cells (DCs), squeezed DCs were ∼1000-fold more potent at eliciting CD8+ T cell responses than DCs cross-presenting the same amount of protein Ag. The approach also enabled engineering of less conventional APCs, such as T cells, for effective priming of CD8+ T cells in vitro and in vivo. Mixtures of immune cells, such as murine splenocytes, also elicited CD8+ T cell responses in vivo when squeezed with Ag. We demonstrate that squeezing enables effective MHC class I presentation by human DCs, T cells, B cells, and PBMCs and that, in clinical scale formats, the system can squeeze up to 2 billion cells per minute. Using the human papillomavirus 16 (HPV16) murine model, TC-1, we demonstrate that squeezed B cells, T cells, and unfractionated splenocytes elicit antitumor immunity and correlate with an influx of HPV-specific CD8+ T cells such that >80% of CD8s in the tumor were HPV specific. Together, these findings demonstrate the potential of cytosolic Ag delivery to drive robust CD8+ T cell responses and illustrate the potential for an autologous cell-based vaccine with minimal turnaround time for patients.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Harry An
- SQZ Biotechnologies, Watertown, MA
| | - Sophia Liu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA
| | - Shirley Mao
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA
| | - Megan Heimann
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA
| | | | | | | | | | | | - Ulrich H von Andrian
- Department of Immunology, Harvard Medical School, Boston, MA.,Ragon Institute of MGH, MIT, and Harvard, Boston, MA.,Center for Immune Imaging at Harvard Medical School, Boston, MA
| | - Klavs F Jensen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA
| | - Robert Langer
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA.,David Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA
| | - Hendrik Knoetgen
- Roche Innovation Center Basel, Roche Pharmaceutical Research and Early Development, Basel, Switzerland; and
| | - Christine Trumpfheller
- Roche Innovation Center Zurich, Roche Pharmaceutical Research and Early Development, Schlieren, Switzerland
| | - Pablo Umaña
- Roche Innovation Center Zurich, Roche Pharmaceutical Research and Early Development, Schlieren, Switzerland
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Loughhead S, Booty M, Hlavaty K, Vicente-Suarez A, Blagovic K, Myint M, Stokes B, Yarar D, Bernstein H, Sharei A. SQZing cells to rapidly generate antigen presenting cells (APC) for solid tumor immune therapies with efficient, scalable manufacturing. Ann Oncol 2018. [DOI: 10.1093/annonc/mdy485.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Henkanatte-Gedera S, Selvaratnam T, Karbakhshravari M, Myint M, Nirmalakhandan N, Van Voorhies W, Lammers PJ. Removal of dissolved organic carbon and nutrients from urban wastewaters by Galdieria sulphuraria: Laboratory to field scale demonstration. ALGAL RES 2017. [DOI: 10.1016/j.algal.2016.08.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Myint M, Loughhead S, Merino A, Tian L, Bernstein H, Sharei A. Vector-Free Engineering of Antigen Presenting Cells for Adoptive Immunotherapies for the Treatment of Cancer. The Journal of Immunology 2017. [DOI: 10.4049/jimmunol.198.supp.73.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
In recent years, ex vivo manipulation of primary cells has shown immense clinical potential with the advent of adoptive T cell therapies. Conventional methods for ex vivo manipulation, however, are not without limitations. They typically rely on the application of electrical fields or exogenous materials such as viral vectors and plasmids, which can increase the potential for cellular toxicity and off-target effects. To overcome such limitations, we have developed an approach using our CellSqueeze Technology that causes temporary membrane disruption as cells are passed through a microfluidic constriction. While the membrane is disrupted, material in the surrounding buffer can diffuse directly into the cytosol. This system has demonstrated efficacy in patient-derived cells, such as stem cells and immune cells, and with a variety of molecules that are difficult to address with alternative methods.
In this work, we describe the use of our vector-free technology to deliver antigens directly to the cytoplasm of antigen-presenting cells (APCs) to drive potent antigen-specific CD8 T cell responses. Conventional methods for eliciting T cell responses with APCs typically rely on cross-presentation, which can be inefficient and require lengthy cultures. Our results show that murine APCs processed with our CellSqueeze Technology can stimulate enhanced antigen-specific T cell responses in vitro and in vivo by at least 3-fold, when compared to responses stimulated by endocytosis controls. Additionally, we show translation of these significant advantages of the CellSqueeze Technology to human APCs, reinforcing the exciting clinical potential of CellSqueeze for adoptive cell therapy.
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Myint M, Bucki R, Janmey PA, Diamond SL. Synthesis and structure-activity relationships of novel cationic lipids with anti-inflammatory and antimicrobial activities. Bioorg Med Chem Lett 2015; 25:2837-43. [PMID: 26004577 DOI: 10.1016/j.bmcl.2015.04.104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 04/23/2015] [Accepted: 04/30/2015] [Indexed: 11/18/2022]
Abstract
Certain membrane-active cationic steroids are known to also possess both anti-inflammatory and antimicrobial properties. This combined functionality is particularly relevant for potential therapies of infections associated with elevated tissue damage, for example, cystic fibrosis airway disease, a condition characterized by chronic bacterial infections and ongoing inflammation. In this study, six novel cationic glucocorticoids were synthesized using beclomethasone, budesonide, and flumethasone. Products were either monosubstituted or disubstituted, containing one or two steroidal groups, respectively. In vitro evaluation of biological activities demonstrated dual anti-inflammatory and antimicrobial properties with limited cytotoxicity for all synthesized compounds. Budesonide-derived compounds showed the highest degree of both glucocorticoid and antimicrobial properties within their respective mono- and disubstituted categories. Structure-activity analyses revealed that activity was generally related to the potency of the parent glucocorticoid. Taken together, these data indicate that these types of dual acting cationic lipids can be synthesized with the appropriate starting steroid to tailor activities as desired.
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Affiliation(s)
- Melissa Myint
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert Bucki
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok, Poland
| | - Paul A Janmey
- Institute for Medicine and Engineering, Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Scott L Diamond
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Kamat V, Paluru P, Myint M, French DL, Gadue P, Diamond SL. MicroRNA screen of human embryonic stem cell differentiation reveals miR-105 as an enhancer of megakaryopoiesis from adult CD34+ cells. Stem Cells 2014; 32:1337-46. [PMID: 24446170 DOI: 10.1002/stem.1640] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 12/03/2013] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) can control stem cell differentiation by targeting mRNAs. Using 96-well plate electroporation, we screened 466 human miRNA mimics by four-color flow cytometry to explore differentiation of common myeloid progenitors (CMP) derived from human embryonic stem cells (hESCs). The transfected cells were then cultured in a cytokine cocktail that supported multiple hematopoietic lineages. At 4-5 days post-transfection, flow cytometry of erythroid (CD235(+)CD41(-)), megakaryocyte (CD41(+)CD42(+)), and myeloid (CD18(+)CD235(-)) lineages revealed miR-105 as a novel enhancer of megakaryocyte production during in vitro primitive hematopoiesis. In hESC-derived CMPs, miR-105 caused a sixfold enhancement in megakaryocyte production. miR-513a, miR-571, and miR-195 were found to be less potent megakaryocyte enhancers. We confirmed the relevance of miR-105 in adult megakaryopoiesis by demonstrating increased megakaryocyte yield and megakaryocyte colony forming potential in human adult CD34(+) cells derived from peripheral blood. In addition, adult CD34(+) cells express endogenous miR-105 during megakaryocyte differentiation. siRNA knockdown of the hematopoietic transcription factor c-Myb caused a similar enhancement of megakaryocyte production as miR-105. Finally, a luciferase/c-Myb-3'UTR construct and Western blot analysis demonstrated that the hematopoietic transcription factor c-Myb mRNA was a target of miR-105. We report a novel hESC-based miR screening platform and demonstrate that miR-105 is an enhancer of megakaryopoiesis in both primitive and definitive hematopoiesis.
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Affiliation(s)
- Viraj Kamat
- Institute for Medicine and Engineering, Department of Chemical and Biomolecular Engineering, 1024 Vagelos Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Myint M, Limberis MP, Bell P, Somanathan S, Haczku A, Wilson JM, Diamond SL. In vivo evaluation of adeno-associated virus gene transfer in airways of mice with acute or chronic respiratory infection. Hum Gene Ther 2014; 25:966-76. [PMID: 25144316 DOI: 10.1089/hum.2014.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Patients with cystic fibrosis (CF) often suffer chronic lung infection with concomitant inflammation, a setting that may reduce the efficacy of gene transfer. While gene therapy development for CF often involves viral-based vectors, little is known about gene transfer in the context of an infected airway. In this study, three mouse models were established to evaluate adeno-associated virus (AAV) gene transfer in such an environment. Bordetella bronchiseptica RB50 was used in a chronic, nonlethal respiratory infection in C57BL/6 mice. An inoculum of ∼10(5) CFU allowed B. bronchiseptica RB50 to persist in the upper and lower respiratory tracts for at least 21 days. In this infection model, administration of an AAV vector on day 2 resulted in 2.8-fold reduction of reporter gene expression compared with that observed in uninfected controls. Postponement of AAV administration to day 14 resulted in an even greater (eightfold) reduction of reporter gene expression, when compared with uninfected controls. In another infection model, Pseudomonas aeruginosa PAO1 was used to infect surfactant protein D (SP-D) or surfactant protein A (SP-A) knockout (KO) mice. With an inoculum of ∼10(5) CFU, infection persisted for 2 days in the nasal cavity of either mouse model. Reporter gene expression was approximately ∼2.5-fold lower compared with uninfected mice. In the SP-D KO model, postponement of AAV administration to day 9 postinfection resulted in only a two fold reduction in reporter gene expression, when compared with expression seen in uninfected controls. These results confirm that respiratory infections, both ongoing and recently resolved, decrease the efficacy of AAV-mediated gene transfer.
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Affiliation(s)
- Melissa Myint
- 1 Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania , Philadelphia, PA 19104
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Boghigian BA, Myint M, Wu J, Pfeifer BA. Simultaneous production and partitioning of heterologous polyketide and isoprenoid natural products in an Escherichia coli two-phase bioprocess. J Ind Microbiol Biotechnol 2011; 38:1809-20. [PMID: 21487833 PMCID: PMC9871370 DOI: 10.1007/s10295-011-0969-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 03/26/2011] [Indexed: 01/26/2023]
Abstract
Natural products have long served as rich sources of drugs possessing a wide range of pharmacological activities. The discovery and development of natural product drug candidates is often hampered by the inability to efficiently scale and produce a molecule of interest, due to inherent qualities of the native producer. Heterologous biosynthesis in an engineering and process-friendly host emerged as an option to produce complex natural products. Escherichia coli has previously been utilized to produce complex precursors to two popular natural product drugs, erythromycin and paclitaxel. These two molecules represent two of the largest classes of natural products, polyketides and isoprenoids, respectively. In this study, we have developed a platform E. coli strain capable of simultaneous production of both product precursors at titers greater than 15 mg l(-1). The utilization of a two-phase batch bioreactor allowed for very strong in situ separation (having a partitioning coefficient of greater than 5,000), which would facilitate downstream purification processes. The system developed here could also be used in metagenomic studies to screen environmental DNA for natural product discovery and preliminary production experiments.
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Affiliation(s)
- Brett A Boghigian
- Department of Chemical and Biological Engineering, Science and Technology Center, Tufts University, 4 Colby Street, Medford, MA 02155, USA
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Gopal S, Green N, Myint M, Jacobs A. Outcome prediction in haematological patients requiring admission to the ICU. Crit Care 2011. [PMCID: PMC3068440 DOI: 10.1186/cc9931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Wu J, Boghigian BA, Myint M, Zhang H, Zhang S, Pfeifer BA. Construction and performance of heterologous polyketide-producing K-12- and B-derived Escherichia coli. Lett Appl Microbiol 2010; 51:196-204. [PMID: 20565574 DOI: 10.1111/j.1472-765x.2010.02880.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Escherichia coli has emerged as a viable heterologous host for the production of complex, polyketide natural compounds. In this study, polyketide biosynthesis was compared between different E. coli strains for the purpose of better understanding and improving heterologous production. METHODS AND RESULTS Both B and K-12 E. coli strains were genetically modified to support heterologous polyketide biosynthesis [specifically, 6-deoxyerythronolide B (6dEB)]. Polyketide production was analysed using a helper plasmid designed to overcome rare codon usage within E. coli. Each strain was analysed for recombinant protein production, precursor consumption, by-product production, and 6dEB biosynthesis. Of the strains tested for biosynthesis, 6dEB production was greatest for E. coli B strains. When comparing biosynthetic improvements as a function of mRNA stability vs codon bias, increased 6dEB titres were observed when additional rare codon tRNA molecules were provided. CONCLUSIONS Escherichia coli B strains and the use of tRNA supplementation led to improved 6dEB polyketide titres. SIGNIFICANCE AND IMPACT OF THE STUDY Given the medicinal potential and growing field of polyketide heterologous biosynthesis, the current study provides insight into host-specific genetic backgrounds and gene expression parameters aiding polyketide production through E. coli.
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Affiliation(s)
- J Wu
- State Key Laboratory of Bioreactor Engineering, National Engineering Research Center for Biotechnology, East China University of Science & Technology, Shanghai, China
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Thwin SS, Soe MM, Myint M, Than M, Lwin S. Variations of the origin and branches of the external carotid artery in a human cadaver. Singapore Med J 2010; 51:e40-e42. [PMID: 20358142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We report a unique variation in the origin and branches of both the left and right external carotid artery (ECA) found during the dissection of a human cadaver. Knowledge of the possible anatomical variations of the ECA is especially important in facio-maxillary and neck surgeries. Surgeons need to be aware of the possibility of encountering such variations, as they may lead to difficulties in differentiating between the external and internal carotid arteries, and in identifying the branches and origins. This knowledge is also important for radiologists in the image interpretation of the face and neck regions.
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Affiliation(s)
- S S Thwin
- Department of Anatomy, Universiti Kuala Lumpur Royal College of Medicine Perak, 3 Jalan Greentown, Ipoh, Malaysia.
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Myint M, Nirmalakhandan N, Speece RE. Anaerobic fermentation of cattle manure: modeling of hydrolysis and acidogenesis. Water Res 2007; 41:323-32. [PMID: 17141822 DOI: 10.1016/j.watres.2006.10.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Revised: 09/14/2006] [Accepted: 10/12/2006] [Indexed: 05/12/2023]
Abstract
A mathematical model for the hydrolysis and acidogenesis reactions in anaerobic digestion of cattle manure is presented. This model is based on the premise that particulate hydrolysable fraction of cattle manure is composed of cellulose and hemicellulose that are hydrolyzed at different rates according to a surface-limiting reaction; and, that the respective soluble products of hydrolysis are utilized by acidogens at different rates, according to a two-substrate, single-biomass model. Batch experimental results were used to identify the sensitive parameters and to calibrate and validate the model. Results predicted by the model agreed well with the experimentally measured data not used in the calibration process, with correlation coefficient exceeding 0.91. These results indicate that the most significant parameter in the hydrolysis-acidogenesis phase is the hydrolysis rate constant for the cellulose fraction.
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Affiliation(s)
- M Myint
- Civil Engineering Department, MSC 3CE, New Mexico State University, Las Cruces, NM 88003, USA
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16
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Myint M, Yuan ZN, Schenck K. Reduced numbers of Langerhans cells and increased HLA-DR expression in keratinocytes in the oral gingival epithelium of HIV-infected patients with periodontitis. J Clin Periodontol 2000; 27:513-9. [PMID: 10914893 DOI: 10.1034/j.1600-051x.2000.027007513.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND HIV-seropositive (HIV+) patients become increasingly susceptible to periodontal diseases as HIV infection proceeds. We have previously shown that HIV+ patients with chronic marginal periodontitis (CMP) have remarkably increased numbers of gingival plasma cells in the connective tissue underlying the oral gingival epithelium, but depressed specific serum IgG levels towards periodontopathogenic bacteria. Langerhans cells (LC) and keratinocytes (KC) are antigen-presenting cells that are important in promoting immune responses. METHOD In this study we examined, by means of immunofluorescence, the distribution and numbers of LC and activated KC in biopsies taken from inflamed periodontal sites in HIV+ and HIV patients with CMP. RESULTS In the pocket epithelium in both patient groups, basal layer KC expressed HLA-DR molecules. In the oral gingival epithelium of HIV+ patients, basal layer KC also expressed HLA-DR molecules and numbers of LC were decreased as compared with HIV persons. CONCLUSION The findings suggest that the oral gingiva in HIV+ patients may be affected by inflammation.
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Affiliation(s)
- M Myint
- Department of Oral Biology, University of Oslo, Norway
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Affiliation(s)
- MV Kalayoglu
- Department of Medical Microbiology and Immunology, University of Wisconsin Medical School, Madison, WI 53706, USA. mkalayog@students. wisc.edu
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Myint M. Orthopaedic surgery. Singapore Med J 1999; 40:721-2. [PMID: 10709418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- M Myint
- Myanmar Medical Association, Yangon, Myanmar
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Myint M, Odden K, Schreurs O, Halstensen TS, Schenck K. The gingival plasma cell infiltrate in HIV-positive patients with periodontitis is disorganized. J Clin Periodontol 1999; 26:358-65. [PMID: 10382575 DOI: 10.1034/j.1600-051x.1999.260605.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Patients infected with the human immunodeficiency virus (HIV) are highly susceptible to chronic marginal periodontitis (CMP) and the lesion is generally characterized by abundant plasma cell infiltration. HIV-induced reduction of CD4+ T cells may indirectly affect local production of immunoglobulins (Ig). Gingival biopsies taken from 10 HIV+ and 12 HIV- control patients with CMP were washed, fixed in ethanol and embedded in paraffin. Sections were examined after immunohistochemical staining with monoclonal antibodies against IgA, IgA1-2, IgG, IgG1-4, IgM and IgE. Ig-containing cells were counted in 3 separate connective tissue zones (subjacent to pocket epithelium, central zone and subjacent to oral epithelium). HIV+ patients showed a remarkably increased density of all Ig-containing cells in the connective tissue zone subjacent to the oral epithelium (p<0.05) and a lower % of IgG2+ cells in the entire gingival section (p<0.05). In HIV+ patients, the density of IgG-containing cells in the gingiva was strongly correlated with the serum IgG concentration. The altered topical distribution might imply impaired restriction of the inflammatory lesion, additional antigenic challenges by unusual microorganisms in the oral cavity, or be secondary to HIV-induced dysregulation of the B-cell system.
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Affiliation(s)
- M Myint
- Department of Oral Biology, University of Oslo, Norway.
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Miller JH, Fedoronko DA, Hass BD, Myint M, Kempner ES. Radiation effects on the native structure of proteins: fragmentation without dissociation. Arch Biochem Biophys 1998; 352:281-7. [PMID: 9587417 DOI: 10.1006/abbi.1998.0604] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several proteins (avidin, carboxypeptidase B, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, maltase, and peroxidase) composed of one to six subunits were irradiated in the frozen state. Each irradiated protein was examined by size-exclusion chromatography (SEC) and by denaturing gel electrophoresis (SDS-PAGE). All these proteins eluted from SEC as a single peak even though SDS-PAGE showed cleavage of the polypeptide backbone of the monomers. Thus, fragmentation of the subunits did not result in dissociation of the oligomeric structure.
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Affiliation(s)
- J H Miller
- Laboratory of Physical Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Steinsvoll S, Myint M, Odden K, Berild D, Schenck K. Reduced serum IgG reactivities with bacteria from dental plaque in HIV-infected persons with periodontitis. J Clin Periodontol 1997; 24:823-9. [PMID: 9402504 DOI: 10.1111/j.1600-051x.1997.tb01196.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Serum samples were obtained from 44 HIV-seropositive (HIV+) and 37 HIV-seronegative (HIV-) persons that were grouped according to periodontal status. Serum IgG and IgA reactivities towards Streptococcus mutans, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis. Prevotella intermedia, Prevotella nigrescens and Fusobacterium nucleatum were measured by means of ELISA. HIV+ persons with chronic marginal periodontitis showed significantly lower IgG reactivities to the periodontal pathogens A. actinomycetemcomitans, P. gingivalis, P. intermedia and F. nucleatum as compared with their HIV- counterparts (p < 0.05). Specific serum IgA reactivities were similar in the two periodontitis groups, except for P. nigrescens where the HIV+ group with chronic marginal periodontitis had lower values than their systemically healthy counterparts (p < 0.05). The results indicate that HIV infection affects the humoral serum immune responses against bacteria in dental plaque; the depressed antibody responses may contribute to the increased susceptibility for periodontal infections in HIV-infected patients.
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Affiliation(s)
- S Steinsvoll
- Department of Oral Biology, University of Oslo, Norway
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Kolaczynski JW, Considine RV, Ohannesian J, Marco C, Opentanova I, Nyce MR, Myint M, Caro JF. Responses of leptin to short-term fasting and refeeding in humans: a link with ketogenesis but not ketones themselves. Diabetes 1996; 45:1511-5. [PMID: 8866554 DOI: 10.2337/diab.45.11.1511] [Citation(s) in RCA: 259] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We investigated the response of leptin to short-term fasting and refeeding in humans. A mild decline in subcutaneous adipocyte ob gene mRNA and a marked fall in serum leptin were observed after 36 and 60 h of fasting. The dynamics of the leptin decline and rise were further substantiated in a 6-day study consisting of a 36-h baseline period, followed by 36-h fast, and a subsequent refeeding with normal diet. Leptin began a steady decline from the baseline values after 12 h of fasting, reaching a nadir at 36 h. The subsequent restoration of normal food intake was associated with a prompt leptin rise and a return to baseline values 24 h later. When responses of leptin to fasting and refeeding were compared with that of glucose, insulin, fatty acids, and ketones, a reverse relationship between leptin and beta-OH-butyrate was found. Consequently, we tested whether the reciprocal responses represented a causal relationship between leptin and beta-OH-butyrate. Small amounts of infused glucose equal to the estimated contribution of gluconeogenesis, which was sufficient to prevent rise in ketogenesis, also prevented a fall in leptin. The infusion of beta-OH-butyrate to produce hyperketonemia of the same magnitude as after a 36-h fast had no effect on leptin. The study indicates that one of the adaptive physiological responses to fasting is a fall in serum leptin. Although the mediator that brings about this effect remains unknown, it appears to be neither insulin nor ketones.
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Affiliation(s)
- J W Kolaczynski
- Division of Endocrinology and Metabolic Diseases, Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Myint M, Atten MJ, Attar BM, Nadimpalli V. Gastric lipoma with severe hemorrhage. Am J Gastroenterol 1996; 91:811-2. [PMID: 8677963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- M Myint
- Department of Medicine, Cook County Hospital, Chicago, Illinois, USA
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Paquet V, Myint M, Roque C, Soucaille P. Partitioning of pristinamycins in aqueous two-phase systems: A first step toward the development of antibiotic production by extractive fermentation. Biotechnol Bioeng 1994; 44:445-51. [DOI: 10.1002/bit.260440407] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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