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Sahu S, Chauhan P, Lumen E, Moody K, Peddireddy K, Mani N, Subramanian R, Robertson-Anderson R, Wolfe AJ, Ross JL. Interplay of self-organization of microtubule asters and crosslinking protein condensates. PNAS Nexus 2023; 2:pgad231. [PMID: 37497046 PMCID: PMC10367440 DOI: 10.1093/pnasnexus/pgad231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 06/28/2023] [Accepted: 07/03/2023] [Indexed: 07/28/2023]
Abstract
The cytoskeleton is a major focus of physical studies to understand organization inside cells given its primary role in cell motility, cell division, and cell mechanics. Recently, protein condensation has been shown to be another major intracellular organizational strategy. Here, we report that the microtubule crosslinking proteins, MAP65-1 and PRC1, can form phase separated condensates at physiological salt and temperature without additional crowding agents in vitro. The size of the droplets depends on the concentration of protein. MAP65 condensates are liquid at first and can gelate over time. We show that these condensates can nucleate and grow microtubule bundles that form asters, regardless of the viscoelasticity of the condensate. The droplet size directly controls the number of projections in the microtubule asters, demonstrating that the MAP65 concentration can control the organization of microtubules. When gel-like droplets nucleate and grow asters from a shell of tubulin at the surface, the microtubules are able to re-fluidize the MAP65 condensate, returning the MAP65 molecules to solution. This work implies that there is an interplay between condensate formation from microtubule-associated proteins, microtubule organization, and condensate dissolution that could be important for the dynamics of intracellular organization.
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Affiliation(s)
- Sumon Sahu
- Physics Department, Syracuse University, Syracuse, NY 13244, USA
- Department of Physics, New York University, New York, NY 10003, USA
| | - Prashali Chauhan
- Physics Department, Syracuse University, Syracuse, NY 13244, USA
- The Bioinspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Ellie Lumen
- Ichor Life Sciences, Inc., 2561 US Route 11, LaFayette, NY 13084, USA
| | - Kelsey Moody
- The Bioinspired Institute, Syracuse University, Syracuse, NY 13244, USA
- Ichor Life Sciences, Inc., 2561 US Route 11, LaFayette, NY 13084, USA
- Lewis School of Health Sciences, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, USA
| | | | - Nandini Mani
- Massachusetts General Hospital, Boston, MA 02115, USA
| | | | | | - Aaron J Wolfe
- The Bioinspired Institute, Syracuse University, Syracuse, NY 13244, USA
- Ichor Life Sciences, Inc., 2561 US Route 11, LaFayette, NY 13084, USA
- Lewis School of Health Sciences, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, USA
| | - Jennifer L Ross
- Physics Department, Syracuse University, Syracuse, NY 13244, USA
- The Bioinspired Institute, Syracuse University, Syracuse, NY 13244, USA
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Rahnemai-Azar A, Lotfinaghsh A, Gortes F, Nygard A, Mani N. Abstract No. 598 Effectiveness of Endovascular Procedures in Severe Life Threatening Post-Partum Hemorrhage in Preventing Peripartum Hysterectomy. J Vasc Interv Radiol 2023. [DOI: 10.1016/j.jvir.2022.12.456] [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: 02/27/2023] Open
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3
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Van Den Broek WWA, Mani N, Azzahhafi J, Berg JT. Poster No. 052 The Influence of the CYP2C9 polymorphisms on the treatment with clopidogrel: combined data from the POPular Genetics & POPular AGE trials. Cardiovasc Res 2022. [DOI: 10.1093/cvr/cvac157.058] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
The CYP2C9-enzym plays a role in the metabolization of clopidogrel. In patients treated with clopidogrel, carriage of a CYP2C9 loss-of-function (LoF) allele has been associated with attenuated pharmacokinetics leading to a diminished pharmacodynamic response and increased risk for stent thrombosis.
Material and methods
We aimed to determine the effect of the CYP2C9*2 and *3 LoF-alleles on thrombotic events and clopidogrel treatment discontinuation. A post-hoc analysis was performed in patients with available CYP2C9 genotype status included in the POPular Genetics and POPular Age trials, which enrolled patients with ST-elevation myocardial infarction and non-ST-elevation myocardial infarction, respectively. The primary thrombotic outcome was a composite of cardiovascular death, myocardial infarction or stroke.
Results
The CYP2C9 genotype was available in 2,257 patients, of which 878 were treated with clopidogrel (352 [40%] CYP2C9 LoF-allele carriers and 526 [60%] CYP2C9 LoF-allele noncarriers). There were no significant differences between CYP2C9 LoF-allele carriers and noncarriers for the combined thrombotic outcome (6.3% vs. 5.9%, HR 1.17 [0.67–2.03], P = 0.58), and the individual thrombotic outcomes. No differences were seen in clinically relevant bleeding (Bleeding Academic Research Consortium [BARC] 2–5 bleeding) as well as major bleeding (BARC 3 or 5 bleeding). Discontinuation rates for clopidogrel due to side-effects were numerically lower in CYP2C9 LoF carriers compared noncarriers (1.4% vs. 3.2%, HR 0.54 [0.26–1.13], P = 0.10), however this difference was not statistically significant.
Conclusions
Carriage of the CYP2C9 *2 or *3 LoF-alleles did not show an association with an increased thrombotic risk in patients treated with clopidogrel.
Funding
ZonMW.
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Affiliation(s)
| | - N Mani
- St. Antonius Hospital , Nieuwegein , Netherlands
| | - J Azzahhafi
- St. Antonius Hospital , Nieuwegein , Netherlands
| | - J Ten Berg
- St. Antonius Hospital , Nieuwegein , Netherlands
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Marlow J, Jabboure F, Mani N, Rostambeigi N. Abstract No. 561 Risk factors of new onset or worsening ascites after Y-90 radioembolization of primary liver tumors. J Vasc Interv Radiol 2022. [DOI: 10.1016/j.jvir.2022.03.543] [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: 11/24/2022] Open
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Chahal A, Kavali P, Mani N. Abstract No. 326 Outcomes of endovascular treatment for symptomatic recurrence after surgical decompression of venous thoracic outlet syndrome (vTOS). J Vasc Interv Radiol 2022. [DOI: 10.1016/j.jvir.2022.03.407] [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: 10/18/2022] Open
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6
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Pokala N, Mani N, Kim S, Kavali P. Abstract No. 166 Cryoablation vs. microwave ablation in the treatment of hepatocellular carcinoma. J Vasc Interv Radiol 2022. [DOI: 10.1016/j.jvir.2022.03.247] [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: 10/18/2022] Open
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Mani N, Marchan MF, Subramanian R. Simultaneous Visualization of the Dynamics of Crosslinked and Single Microtubules In Vitro by TIRF Microscopy. J Vis Exp 2022:10.3791/63377. [PMID: 35253794 PMCID: PMC9914519 DOI: 10.3791/63377] [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: 10/31/2022]
Abstract
Microtubules are polymers of αβ-tubulin heterodimers that organize into distinct structures in cells. Microtubule-based architectures and networks often contain subsets of microtubule arrays that differ in their dynamic properties. For example, in dividing cells, stable bundles of crosslinked microtubules coexist in close proximity to dynamic non-crosslinked microtubules. TIRF-microscopy-based in vitro reconstitution studies enable the simultaneous visualization of the dynamics of these different microtubule arrays. In this assay, an imaging chamber is assembled with surface-immobilized microtubules, which are either present as single filaments or organized into crosslinked bundles. Introduction of tubulin, nucleotides, and protein regulators allows direct visualization of associated proteins and of dynamic properties of single and crosslinked microtubules. Furthermore, changes that occur as dynamic single microtubules organize into bundles can be monitored in real-time. The method described here allows for a systematic evaluation of the activity and localization of individual proteins, as well as synergistic effects of protein regulators on two different microtubule subsets under identical experimental conditions, thereby providing mechanistic insights that are inaccessible by other methods.
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Affiliation(s)
- Nandini Mani
- Molecular Biology, Massachusetts General Hospital,Department of Genetics, Harvard Medical School
| | | | - Radhika Subramanian
- Molecular Biology, Massachusetts General Hospital; Department of Genetics, Harvard Medical School;
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Mani N, Wijeratne SS, Subramanian R. Micron-scale geometrical features of microtubules as regulators of microtubule organization. eLife 2021; 10:e63880. [PMID: 34114950 PMCID: PMC8195601 DOI: 10.7554/elife.63880] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/02/2021] [Indexed: 12/20/2022] Open
Abstract
The organization of micron-sized, multi-microtubule arrays from individual microtubules is essential for diverse cellular functions. The microtubule polymer is largely viewed as a passive building block during the organization process. An exception is the 'tubulin code' where alterations to tubulin at the amino acid level can influence the activity of microtubule-associated proteins. Recent studies reveal that micron-scale geometrical features of individual microtubules and polymer networks, such as microtubule length, overlap length, contact angle, and lattice defects, can also regulate the activity of microtubule-associated proteins and modulate polymer dynamics. We discuss how the interplay between such geometrical properties of the microtubule lattice and the activity of associated proteins direct multiple aspects of array organization, from microtubule nucleation and coalignment to specification of array dimensions and remodeling of dynamic networks. The mechanisms reviewed here highlight micron-sized features of microtubules as critical parameters to be routinely investigated in the study of microtubule self-organization.
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Affiliation(s)
- Nandini Mani
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Sithara S Wijeratne
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
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Mani N, Jiang S, Neary AE, Wijeratne SS, Subramanian R. Differential regulation of single microtubules and bundles by a three-protein module. Nat Chem Biol 2021; 17:964-974. [PMID: 34083810 PMCID: PMC8387365 DOI: 10.1038/s41589-021-00800-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/19/2021] [Indexed: 12/15/2022]
Abstract
A remarkable feature of the microtubule cytoskeleton is co-existence of sub-populations having different dynamic properties. A prominent example is the anaphase spindle, where stable antiparallel bundles exist alongside dynamic microtubules and provide spatial cues for cytokinesis. How are dynamics of spatially proximal arrays differentially regulated? We reconstitute a minimal system of three midzone proteins: microtubule-crosslinker PRC1, and its interactors CLASP1 and Kif4A, proteins that promote and suppress microtubule elongation, respectively. We find their collective activity promotes elongation of single microtubules, while simultaneously stalling polymerization of crosslinked bundles. This differentiation arises from (i) Strong rescue activity of CLASP1, which overcomes weaker effects of Kif4A on single microtubules, (ii) Lower microtubule and PRC1-binding affinity of CLASP1, which permit dominance of Kif4A at overlaps. In addition to canonical mechanisms where antagonistic regulators set microtubule lengths, our findings illuminate design principles by which collective regulator activity creates microenvironments of arrays with distinct dynamic properties.
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Affiliation(s)
- Nandini Mani
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Shuo Jiang
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Alex E Neary
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Sithara S Wijeratne
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA. .,Department of Genetics, Harvard Medical School, Boston, MA, USA.
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10
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Mani N, Jiang S, Neary AE, Wijeratne SS, Subramanian R. Differential Regulation of Single Microtubules and Cross-Linked Bundles by a Minimal Three-Protein Module. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1658] [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: 11/27/2022] Open
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11
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Kim D, Mani N, Darcy M, Kim S. Abstract No. 647 Outcomes of transjugular intrahepatic portosystemic shunt creation in patients with elevated intraprocedural right heart pressures. J Vasc Interv Radiol 2020. [DOI: 10.1016/j.jvir.2019.12.708] [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: 11/27/2022] Open
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12
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Davies M, Rimer R, Kim S, Kavali P, Mani N. Abstract No. 575 Effectiveness of transrectal and transvaginal drainage of pelvic fluid collections: an analysis based on etiological classification: a large single-institution study. J Vasc Interv Radiol 2020. [DOI: 10.1016/j.jvir.2019.12.636] [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: 11/26/2022] Open
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13
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Davies M, Rimer R, Mani N, Kim S, Ramaswamy R, Malone C. Abstract No. 612 Impact of number of inflow lymphatics on efficacy of lymphangiography and embolization of postoperative groin and pelvic lymphoceles. J Vasc Interv Radiol 2020. [DOI: 10.1016/j.jvir.2019.12.673] [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: 10/25/2022] Open
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14
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Velez P, Kim S, Picus D, Mani N. Abstract No. 441 Eventual outcomes of patients undergoing peritoneal dialysis catheter by interventional radiologist: a large single-institution 2-year observational study. J Vasc Interv Radiol 2020. [DOI: 10.1016/j.jvir.2019.12.502] [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: 11/27/2022] Open
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15
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Jiang S, Mani N, Wilson-Kubalek EM, Ku PI, Milligan RA, Subramanian R. Interplay between the Kinesin and Tubulin Mechanochemical Cycles Underlies Microtubule Tip Tracking by the Non-motile Ciliary Kinesin Kif7. Dev Cell 2019; 49:711-730.e8. [PMID: 31031197 DOI: 10.1016/j.devcel.2019.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 03/08/2019] [Accepted: 03/29/2019] [Indexed: 01/08/2023]
Abstract
The correct localization of Hedgehog effectors to the tip of primary cilia is critical for proper signal transduction. The conserved non-motile kinesin Kif7 defines a "cilium-tip compartment" by localizing to the distal ends of axonemal microtubules. How Kif7 recognizes microtubule ends remains unknown. We find that Kif7 preferentially binds GTP-tubulin at microtubule ends over GDP-tubulin in the mature microtubule lattice, and ATP hydrolysis by Kif7 enhances this discrimination. Cryo-electron microscopy (cryo-EM) structures suggest that a rotated microtubule footprint and conformational changes in the ATP-binding pocket underlie Kif7's atypical microtubule-binding properties. Finally, Kif7 not only recognizes but also stabilizes a GTP-form of tubulin to promote its own microtubule-end localization. Thus, unlike the characteristic microtubule-regulated ATPase activity of kinesins, Kif7 modulates the tubulin mechanochemical cycle. We propose that the ubiquitous kinesin fold has been repurposed in Kif7 to facilitate organization of a spatially restricted platform for localization of Hedgehog effectors at the cilium tip.
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Affiliation(s)
- Shuo Jiang
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Nandini Mani
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Elizabeth M Wilson-Kubalek
- Department of Integrative Structural and Computational Biology, Scripps Research, La Jolla, CA 92037, USA
| | - Pei-I Ku
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Ronald A Milligan
- Department of Integrative Structural and Computational Biology, Scripps Research, La Jolla, CA 92037, USA
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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Masrani A, Jazmati T, Alahdab F, Mani S, Murad H, Mani N. Abstract No. 579 BRTO vs. TIPS for gastric variceal bleeding secondary to portal hypertension: systematic review and meta-analysis. J Vasc Interv Radiol 2019. [DOI: 10.1016/j.jvir.2018.12.660] [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: 11/29/2022] Open
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Khaddash T, Mokkarala M, Malone C, Kim S, Mani N, Ramaswamy R, Akinwande O. 03:09 PM Abstract No. 432 Effectiveness of carcinoembryonic antigen (CEA) vs. Response Evaluation Criteria in Solid Tumors (RECIST) response as survival predictors for patients with metastatic colorectal cancer following radioembolization (TARE). J Vasc Interv Radiol 2019. [DOI: 10.1016/j.jvir.2018.12.512] [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: 10/27/2022] Open
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18
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Gettinger SN, Choi J, Mani N, Sanmamed MF, Datar I, Sowell R, Du VY, Kaftan E, Goldberg S, Dong W, Zelterman D, Politi K, Kavathas P, Kaech S, Yu X, Zhao H, Schlessinger J, Lifton R, Rimm DL, Chen L, Herbst RS, Schalper KA. A dormant TIL phenotype defines non-small cell lung carcinomas sensitive to immune checkpoint blockers. Nat Commun 2018; 9:3196. [PMID: 30097571 PMCID: PMC6086912 DOI: 10.1038/s41467-018-05032-8] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 06/07/2018] [Indexed: 02/07/2023] Open
Abstract
The biological determinants of sensitivity and resistance to immune checkpoint blockers are not completely understood. To elucidate the role of intratumoral T-cells and their association with the tumor genomic landscape, we perform paired whole exome DNA sequencing and multiplexed quantitative immunofluorescence (QIF) in pre-treatment samples from non-small cell lung carcinoma (NSCLC) patients treated with PD-1 axis blockers. QIF is used to simultaneously measure the level of CD3+ tumor infiltrating lymphocytes (TILs), in situ T-cell proliferation (Ki-67 in CD3) and effector capacity (Granzyme-B in CD3). Elevated mutational load, candidate class-I neoantigens or intratumoral CD3 signal are significantly associated with favorable response to therapy. Additionally, a "dormant" TIL signature is associated with survival benefit in patients treated with immune checkpoint blockers characterized by elevated TILs with low activation and proliferation. We further demonstrate that dormant TILs can be reinvigorated upon PD-1 blockade in a patient-derived xenograft model.
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Affiliation(s)
- S N Gettinger
- Medical Oncology and Yale Cancer Center, New Haven, CT, 06511, USA
| | - J Choi
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06511, USA
| | - N Mani
- Department of Pathology, Yale School of Medicine, New Haven, CT, 06511, USA
- Translational Immuno-oncology Laboratory, Yale Cancer Center, New Haven, CT, 06511, USA
| | - M F Sanmamed
- Immunobiology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - I Datar
- Department of Pathology, Yale School of Medicine, New Haven, CT, 06511, USA
- Translational Immuno-oncology Laboratory, Yale Cancer Center, New Haven, CT, 06511, USA
| | - Ryan Sowell
- Immunobiology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - Victor Y Du
- Immunobiology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - E Kaftan
- Medical Oncology and Yale Cancer Center, New Haven, CT, 06511, USA
- Translational Immuno-oncology Laboratory, Yale Cancer Center, New Haven, CT, 06511, USA
| | - S Goldberg
- Medical Oncology and Yale Cancer Center, New Haven, CT, 06511, USA
| | - W Dong
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06511, USA
| | - D Zelterman
- Yale School of Public Health, New Haven, CT, 06511, USA
| | - K Politi
- Medical Oncology and Yale Cancer Center, New Haven, CT, 06511, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - P Kavathas
- Immunobiology, Yale School of Medicine, New Haven, CT, 06511, USA
- Laboratory Medicine, Yale School of Medicine, New Haven, CT, 06511, USA
| | - S Kaech
- Immunobiology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - X Yu
- Yale School of Public Health, New Haven, CT, 06511, USA
| | - H Zhao
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06511, USA
- Yale School of Public Health, New Haven, CT, 06511, USA
| | - J Schlessinger
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - R Lifton
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06511, USA
| | - D L Rimm
- Medical Oncology and Yale Cancer Center, New Haven, CT, 06511, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - L Chen
- Immunobiology, Yale School of Medicine, New Haven, CT, 06511, USA
| | - R S Herbst
- Medical Oncology and Yale Cancer Center, New Haven, CT, 06511, USA
| | - K A Schalper
- Medical Oncology and Yale Cancer Center, New Haven, CT, 06511, USA.
- Department of Pathology, Yale School of Medicine, New Haven, CT, 06511, USA.
- Translational Immuno-oncology Laboratory, Yale Cancer Center, New Haven, CT, 06511, USA.
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Majumdar S, Shoela R, Kim D, Ramaswamy R, Mani N, Salter A, Akinwande O. Abstract No. 640 Endovascular treatment of SVC syndrome secondary to fibrosing mediastinitis: a feasibility and safety analysis. J Vasc Interv Radiol 2018. [DOI: 10.1016/j.jvir.2018.01.685] [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: 11/24/2022] Open
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Ramaswamy R, Raman H, Jun E, Mani N, Kim S, Akinwande O. Abstract No. 647 Denali, Tulip, and Option inferior vena cava filter retrieval: a single-center experience. J Vasc Interv Radiol 2018. [DOI: 10.1016/j.jvir.2018.01.692] [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: 10/17/2022] Open
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Majumdar S, Akinwande O, Mani N, Picus D, Kim S, Darcy M, Ramaswamy R. Abstract No. 617 Technical predictors of initial transjugular intrahepatic portosystemic shunt dysfunction. J Vasc Interv Radiol 2018. [DOI: 10.1016/j.jvir.2018.01.662] [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: 11/16/2022] Open
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Fung D, Kim S, Ramaswamy R, Salter A, Mani N, Akinwande O. 3:27 PM Abstract No. 36 Comparison of pathologic treatment response between conventional and doxorubicin-eluting bead chemoembolization in explanted livers. J Vasc Interv Radiol 2018. [DOI: 10.1016/j.jvir.2018.01.044] [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: 10/17/2022] Open
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Vajravijayan S, Pletnev S, Mani N, Pletneva N, Nandhagopal N, Gunasekaran K. Structural insights on starch hydrolysis by plant β-amylase and its evolutionary relationship with bacterial enzymes. Int J Biol Macromol 2018; 113:329-337. [PMID: 29481953 DOI: 10.1016/j.ijbiomac.2018.02.138] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/14/2018] [Accepted: 02/22/2018] [Indexed: 11/17/2022]
Abstract
The conversion of starch to maltose is catalysed in plants by β-amylase. The enzymatic mechanism has been well-characterized for the soybean and barley enzymes, which utilise a glutamic acid-glutamate pair. In the present study, we present a surprise observation of maltotetraose at the active site, the presence of which elucidates the clear role of Thr344 as a conformational "switch" between substrate binding and product release during hydrolysis. This observation is confirmed by the selection of maltotetraose by the crystallized enzyme although that carbohydrate was present in only trace amounts. The conformation of the residues in the substrate-binding site changed upon substrate binding, leading to the movement of threonine, glutamic acid, and the loop conformation, elucidating a missing link in the existing mechanism. By aligning our substrate-free and maltotetraose-bound structures with other existing structures, the sequence of events from substrate binding to hydrolysis can be visualized. Apart from this, the evolutionary relationship among β-amylases of bacterial and amyloplastic origin could be established. The presence of a sugar-binding domain in the bacterial enzyme and its absence in the plant counterpart could be attributed to a carbohydrate-rich environment. Interestingly, cladogram analysis indicates the presence of N-terminal additions in some plant β-amylases. Based on sequence similarity, we postulate that the role of such additions is important for the regulation of enzymatic activity, particularly under stress conditions.
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Affiliation(s)
- S Vajravijayan
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
| | - S Pletnev
- Macromolecular Crystallography Laboratory, National Cancer Institute, and Basic Science Program, Leidos Biomedical Research Inc., Argonne, IL 60439, USA
| | - N Mani
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
| | - N Pletneva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russian Federation
| | - N Nandhagopal
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India.
| | - K Gunasekaran
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India.
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Abstract
The present study examined the development of calcium binding protein-containing neurons in a timed series of fetal neocortical transplants. The immunoexpression of parvalbumin and calbindin, which are subpopulations of GABAergic neurons, have been widely studied in normal development and in disease and injury states. Because of their purported resistance to oxidative injury by their ability to buffer Ca++ influx, these neurons have been particularly studied following ischemia. Because it is likely that oxidative stress is associated with the grafting procedure, we sought to determine if these neurons displayed enhanced survival characteristics. Normally, parvalbumin and calbindin represent about 5-10% of cortical neurons. Within 2-4 wk after grafting the expression of both proteins increased markedly in that a relatively larger number of neurons (27% for parvalbumin) were immunopositive. This increase was transitory, however, and by 4 mo and beyond, confocal microscopic data showed a reduction of over 50% of parvalbumin (+) neurons and processes. Calbindin (+) processes showed a qualitative change in that they were smaller with less terminal branching. Electron microscopy confirmed a substantial reduction in parvalbumin synaptic contacts. Interestingly, in older grafts, remaining parvalbumin neurons were those that were strongly NSE (+) suggesting a link between normal metabolism and Ca++ buffering in grafted neurons. It is possible that in early grafts certain neuronal populations transiently upregulated calcium binding proteins as a defensive mechanism against Ca++ influx associated with oxidative stress. Over time, however, following physiological normalization within grafts, the calcium binding protein (+) neurons are diminished, possibly due to lack of appropriate afferent input to the interneuronal pool.
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Affiliation(s)
- J M Rosenstein
- Department of Anatomy and Cell Biology, The George Washington University Medical Center, Washington, DC 20027, USA
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Affiliation(s)
- N Mani
- Central Manchester University Hospitals NHS Foundation Trust , UK
| | - P Bijoor
- Central Manchester University Hospitals NHS Foundation Trust , UK
| | - G Cook
- Central Manchester University Hospitals NHS Foundation Trust , UK
| | - S Loughran
- Central Manchester University Hospitals NHS Foundation Trust , UK
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Mani N, Bhandari S, Moreno R, Hu L, Prasad BVV, Suguna K. Multiple oligomeric structures of a bacterial small heat shock protein. Sci Rep 2016; 6:24019. [PMID: 27053150 PMCID: PMC4823740 DOI: 10.1038/srep24019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 03/14/2016] [Indexed: 11/23/2022] Open
Abstract
Small heat shock proteins are ubiquitous molecular chaperones that form the first line of defence against the detrimental effects of cellular stress. Under conditions of stress they undergo drastic conformational rearrangements in order to bind to misfolded substrate proteins and prevent cellular protein aggregation. Owing to the dynamic nature of small heat shock protein oligomers, elucidating the structural basis of chaperone action and oligomerization still remains a challenge. In order to understand the organization of sHSP oligomers, we have determined crystal structures of a small heat shock protein from Salmonella typhimurium in a dimeric form and two higher oligomeric forms: an 18-mer and a 24-mer. Though the core dimer structure is conserved in all the forms, structural heterogeneity arises due to variation in the terminal regions.
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Affiliation(s)
- Nandini Mani
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Spraha Bhandari
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Rodolfo Moreno
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - Liya Hu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - B V Venkataram Prasad
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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Mani N, Kim S, Gunn A, Varma R. Percutaneous radiologic gastrostomy in patients with amyotrophic lateral sclerosis (ALS) with minimal intravenous analgesia without gastropexy: evaluation of technical success, safety and efficacy. J Vasc Interv Radiol 2016. [DOI: 10.1016/j.jvir.2015.12.470] [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: 10/22/2022] Open
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Aristatil G, Karthikeya S, Mani N, Ingersoll J. Direct Electrodeposition of Graphene and Platinum Based Alloys-Analysis by SEM/EDX. ACTA ACUST UNITED AC 2015. [DOI: 10.3923/ajsr.2015.245.263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Mani N, Ramakrishna K, Suguna K. Characterization of rice small heat shock proteins targeted to different cellular organelles. Cell Stress Chaperones 2015; 20:451-60. [PMID: 25624002 PMCID: PMC4406937 DOI: 10.1007/s12192-015-0570-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [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: 10/30/2014] [Revised: 01/02/2015] [Accepted: 01/06/2015] [Indexed: 12/11/2022] Open
Abstract
Small heat shock proteins (sHSPs) are a family of ATP-independent molecular chaperones which prevent cellular protein aggregation by binding to misfolded proteins. sHSPs form large oligomers that undergo drastic rearrangement/dissociation in order to execute their chaperone activity in protecting substrates from stress. Substrate-binding sites on sHSPs have been predominantly mapped on their intrinsically disordered N-terminal arms. This region is highly variable in sequence and length across species, and has been implicated in both oligomer formation and in mediating chaperone activity. Here, we present our results on the functional and structural characterization of five sHSPs in rice, each differing in their subcellular localisation, viz., cytoplasm, nucleus, chloroplast, mitochondria and peroxisome. We performed activity assays and dynamic light scattering studies to highlight differences in the chaperone activity and quaternary assembly of sHSPs targeted to various organelles. By cloning constructs that differ in the length and sequence of the tag in the N-terminal region, we have probed the sensitivity of sHSP oligomer assembly and chaperone activity to the length and amino acid composition of the N-terminus. In particular, we have shown that the incorporation of an N-terminal tag has significant consequences on sHSP quaternary structure.
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Affiliation(s)
- Nandini Mani
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012 India
| | | | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012 India
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Oguejiofor KK, Hall JS, Mani N, Douglas C, Slevin NJ, Homer J, Hall G, West CML. The prognostic significance of the biomarker p16 in oropharyngeal squamous cell carcinoma. Clin Oncol (R Coll Radiol) 2013; 25:630-8. [PMID: 23916365 DOI: 10.1016/j.clon.2013.07.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [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: 02/22/2013] [Revised: 05/09/2013] [Accepted: 05/14/2013] [Indexed: 01/19/2023]
Abstract
AIMS There is an increasing incidence of human papillomavirus (HPV)-positive oropharyngeal squamous cell cancers (OPSCC) mostly associated with favourable outcomes. p16 immunohistochemistry is a surrogate marker for HPV positivity in OPSCC. The prognostic strength of p16 over traditional prognostic factors is not fully characterised. In this study, we evaluated the clinical and demographic differences between p16-positive and -negative OPSCC and characterised its prognostic strength versus traditional prognostic factors. MATERIALS AND METHODS Formalin-fixed, paraffin-embedded blocks and clinical information from 217 OPSCC patients, treated with radiotherapy (alone or in combination with other therapies) between 2000 and 2010 were collected retrospectively. Immunohistochemistry for p16 protein was carried out; cancer-specific survival (CSS), recurrence-free survival (RFS) and locoregional control (LRC) were calculated for both univariate and multivariate analyses. RESULTS Ninety-two per cent of the OPSCC originated from tonsil and tongue base sites, 61% were p16 positive. Patients with p16-positive OPSCC were younger (P < 0.0001), with lower alcohol (P = 0.0002) and tobacco (P = 0.0001) exposure. The tumours were less differentiated (P = 0.0069), had a lower T stage (P = 0.0027), higher nodal status (P = 0.014) and higher American Joint Committee on Cancer (AJCC) prognostic group (P = 0.0036). AJCC prognostic group was significant for RFS (P = 0.0096) and CSS (P = 0.018) in patients with p16-negative OPSCC, but not those with p16-positive tumours (P = 0.30 and 0.54). Other significant factors for CSS and RFS in univariate analysis were: pretreatment haemoglobin (P < 0.0001 and <0.0001), chemoradiotherapy (P = 0.005 and 0.03) and P16 status (P < 0.0001 and 0.0001). In multivariate analysis, p16 positivity was the strongest independent prognostic variable for both CSS, RFS and LRC (P < 0.0001, hazard ratio 4.15; 95% confidence interval 2.43-7.08), (P < 0.0001, hazard ratio 6.15; 95% confidence interval 3.57-10.61) and (P = 0.001, hazard ratio 3.74; confidence interval 1.76-7.95). CONCLUSION This study shows that p16 is the single most important prognostic variable in OPSCC, surpassing traditional prognostic factors for both CSS and RFS. Furthermore, disease stage has no prognostic significance in p16-positive patients, highlighting the need for routine p16 assessment in OPSCC.
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Affiliation(s)
- K K Oguejiofor
- Translational Radiobiology Group, Institute of Cancer Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
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Mani N, Homer J. Re: Squamous cell carcinoma of the oral tongue in patients younger than 30 years. Clin Otolaryngol 2011; 36:90. [PMID: 21414166 DOI: 10.1111/j.1749-4486.2010.02238.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Fortuna RJ, Robbins BW, Mani N, Halterman JS. Dependence on emergency care among young adults in the United States. J Gen Intern Med 2010; 25:663-9. [PMID: 20306149 PMCID: PMC2881978 DOI: 10.1007/s11606-010-1313-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 01/22/2010] [Accepted: 02/12/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND Young adults have a high prevalence of many preventable diseases and frequently lack a usual source of ambulatory care, yet little is known about their use of the emergency department. OBJECTIVE To characterize care provided to young adults in the emergency department. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional analysis of visits from young adults age 20 to 29 presenting to emergency departments (N = 17,048) and outpatient departments (N = 14,443) in the National Hospital Ambulatory Medical Care Survey and National Ambulatory Medical Care Survey. MAIN MEASURES Visits to the emergency department compared to ambulatory offices. RESULTS Emergency department care accounts for 21.6% of all health care visits from young adults, more than children/adolescents (12.6%; P < 0.001) or patients 30 years and over (8.3%; P < 0.001). Visits from young adults were considerably more likely to occur in the emergency department for both injury-related and non-injury-related reasons compared to children/adolescents (P < 0.001) or older adults (P < 0.001). Visits from black young adults were more likely than whites to occur in the emergency department (36.2% vs.19.2%; P < 0.001) rather than outpatient offices. The proportion of care delivered to black young adults in the emergency department increased between 1996 and 2006 (25.9% to 38.5%; P = 0.001 for trend). In 2006, nearly half (48.5%) of all health care provided to young black men was delivered through emergency departments. The urgency of young adult emergency visits was less than other age groups and few (4.7%) resulted in hospital admission. CONCLUSIONS A considerable amount of care provided to young adults is delivered through emergency departments. Trends suggest that young adults are increasingly relying on emergency departments for health care, while being seen for less urgent indications.
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Affiliation(s)
- Robert J Fortuna
- Center for Primary Care, University of Rochester School of Medicine and Dentistry, Rochester, NY 14609, USA.
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Mani N, Park MO, Jun HW. Microencapsulation of a hydrophilic drug into a hydrophobic matrix using a salting-out procedure. I: Development and optimization of the process using factorial design. J Microencapsul 2008; 21:125-35. [PMID: 15198425 DOI: 10.1080/02652040310001619776] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The congealable disperse phase method for preparing sustained release microspheres involves an emulsification process using water as the external phase and molten hydrophobic wax as the disperse phase into which the drug is loaded. Attempts to entrap highly water-soluble drugs using this process have often resulted in low loading efficiency as the drugs partition into the external water phase during emulsification and are lost. A novel method employing salts and wetting agents was developed to improve the loading efficiency of the highly water-soluble drug, guaifenesin, using this method. The drug/wax ratio (D/W) and the presence of salts and wetting agents greatly influenced microsphere properties. To optimize the process for drug loading efficiency and release rate, three different D/Ws, salts and wetting agents were chosen and a full 3(3) factorial design experiment was performed. Any significant differences among the levels of the variables and their individual and joint effects on entrapment efficiency and T50 (time for 50% drug release) were determined. Entrapment efficiencies in the range 35.1-86.3% were obtained for the various factor-level combinations of the variables. Particle size was in the range 140-385 microm and T50 was 0.59-2.72 h for the microspheres obtained. The D/W and type of salt used significantly affected drug entrapment and T50, while the nature of wetting agent was not significant at p < 0.05. The microspheres prepared using 1:4 D/W showed the highest entrapment efficiency and slowest drug release.
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Affiliation(s)
- N Mani
- Forest Laboratories, Inc., 330 Propsect Street, Inwood, NY 11096, USA
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Mani N, Lowe D. Response to Hobson and Cardozo. Clin Otolaryngol 2007. [DOI: 10.1111/j.1749-4486.2007.01522.x] [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: 11/28/2022]
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Mani N, Malik V, Brewis C, Gray R. Prevention of Airway Fire During Tracheostomy – a Further Precaution. Ann R Coll Surg Engl 2007. [DOI: 10.1308/rcsann.2007.89.8.818] [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: 11/22/2022] Open
Affiliation(s)
- N Mani
- Department of Otolaryngology, Addenbrooke's Hospital Cambridge, UK
| | - V Malik
- Department of Otolaryngology, Addenbrooke's Hospital Cambridge, UK
| | - C Brewis
- Department of Otolaryngology, Addenbrooke's Hospital Cambridge, UK
| | - R Gray
- Department of Otolaryngology, Addenbrooke's Hospital Cambridge, UK
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Mani N, Lowe D, Pope L, El-Daly H, Pfleiderer A. An unusual case of laryngeal spindle cell carcinoma metastasising to the orbit and heart. J Laryngol Otol 2007; 121:e19. [PMID: 17610763 DOI: 10.1017/s0022215107009498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We report the first case in the world literature of laryngeal spindle cell carcinoma metastasising to the orbit. A 65-year-old woman was previously treated for T3 N0 Mx laryngeal spindle cell carcinoma, with laryngectomy and post-operative radiotherapy. Five months following this treatment, she developed proptosis, diplopia and reduced right visual acuity, secondary to an enlarging mass within the right orbit. This was biopsied, and subsequent histology confirmed a diagnosis of metastatic spindle cell carcinoma. Subsequent post-mortem examination demonstrated additional pulmonary, hepatic and cardiac metastatic disease, in the absence of any other primary tumour or locoregional disease. The radiological investigation of patients with laryngeal spindle cell carcinoma is discussed and contrasted with that of laryngeal squamous cell carcinoma.
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Affiliation(s)
- N Mani
- Department of Otolaryngology, Head and Neck Surgery, Peterborough Hospitals NHS Trust, UK
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Abstract
The effects of exogenous vascular endothelial growth factor (VEGF) on angiogenesis, blood-brain barrier permeability and astroglial proliferation in the adult rat CNS in situ were investigated. Recombinant human VEGF(165) (25 or 50 ng/ml) was delivered for up to 1 week using either intracerebral osmotic minipumps or less traumatic subdural gelatin sponge placement. By 3 days, VEGF delivery caused significantly increased cerebral angiogenesis (25 ng/ml was most effective) in both experimental models when compared to saline controls; VEGF infusion resulted in a 100% increase in an index of vascular proliferation, and gelatin sponge delivery produced a 65% increase. The blood-brain barrier hallmark endothelial glucose transporter-1 was not present in nascent vascular sprouts. Infusion of VEGF produced extensive protein leakage that persisted after saline-induced permeability was mostly resolved, while gelatin sponge administration caused milder barrier dysfunction. Administration of the angiogenic factor had unexpected proliferative effects on astroglia in both models, resulting in an 80-85% increase in mitotically active astroglia when compared to controls. Immunohistochemical results and semi-quantitative reverse transcriptase-polymerase chain reaction indicated that the VEGF receptors flk-1 and flt-1 were up-regulated in response to the infusion trauma; flt-1 was localized to reactive astroglia, while flk-1 was expressed in vascular endothelium but predominantly in neuronal somata and processes adjacent to the delivery site. mRNA for the VEGF(121), VEGF(165) and VEGF(188) isoforms was also increased after delivery of the recombinant protein. These data show that VEGF application has substantial proliferative effects on CNS endothelium and astroglia and causes up-regulation of its own message. Flt-1 and flk-1 receptor mRNAs and proteins are up-regulated in both vascular and non-vascular cell types following infusion trauma. From these results we suggest that administered VEGF has heretofore unanticipated pleiotrophic effects in the adult CNS.
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Affiliation(s)
- J M Krum
- Department of Anatomy and Cell Biology, The George Washington University Medical Center, Washington, DC 20037, USA.
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Mani N. [Not Available]. Stud Anc Med 2001; 1:26-49. [PMID: 11618913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Mani N. [Not Available]. Veroff Schweiz Ges Gesch Pharm 2001; 2:181-201. [PMID: 11621309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Abstract
The melting point of lidocaine was significantly lowered when mixed with thymol and/or aqueous ethanol. Mixtures of lidocaine and thymol at ratios within the range of 30:70-70:30 (w:w) became homogeneous oils at 25 degrees C. In a pH 9.2 carbonate buffer containing 25% ethanol, lidocaine (5%, w:w) also liquefied at 25 degrees C. The studies led to the development of novel two-phase melt systems of lidocaine (TMS) which consisted of a highly concentrated oil phase of lidocaine and an alcoholic aqueous phase. A compositional phase diagram showed that in aqueous dispersions of lidocaine, concurrent use of thymol and ethanol depressed the melting point of lidocaine more effectively than when they were used individually. Both thymol and aqueous ethanol were necessary as melting point depressing agents to achieve the highest possible lidocaine concentration of 87% (w:w) in the oil phase of a TMS at 25 degrees C. Containing an internal oil phase and an external aqueous phase at ambient temperature, such a TMS can be readily formulated into topical O/W cream after addition of proper surfactants and thickening agents. In an anesthetic activity test using mouse tail-flick model, a 5% lidocaine cream prepared was highly effective as shown by the prolonged latency time of the mice to a heat stimulus as compared with a placebo (P<0.05).
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Affiliation(s)
- L Kang
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, GA 30602, USA
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Abstract
Clostridium difficile, a causative agent of antibiotic-associated diarrhea and its potentially lethal form, pseudomembranous colitis, produces two large protein toxins that are responsible for the cellular damage associated with the disease. The level of toxin production appears to be critical for determining the severity of the disease, but the mechanism by which toxin synthesis is regulated is unknown. The product of a gene, txeR, that lies just upstream of the tox gene cluster was shown to be needed for tox gene expression in vivo and to activate promoter-specific transcription of the tox genes in vitro in conjunction with RNA polymerases from C. difficile, Bacillus subtilis, or Escherichia coli. TxeR was shown to function as an alternative sigma factor for RNA polymerase. Because homologs of TxeR regulate synthesis of toxins and a bacteriocin in other Clostridium species, TxeR appears to be a prototype for a novel mode of regulation of toxin genes.
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Affiliation(s)
- N Mani
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02211, USA
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Jourlin-Castelli C, Mani N, Nakano MM, Sonenshein AL. CcpC, a novel regulator of the LysR family required for glucose repression of the citB gene in Bacillus subtilis. J Mol Biol 2000; 295:865-78. [PMID: 10656796 DOI: 10.1006/jmbi.1999.3420] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [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: 11/22/2022]
Abstract
Synergistic carbon catabolite repression of the Bacillus subtilis aconitase (citB) gene by glucose and a source of 2-ketoglutarate is dependent on DNA sequences located upstream of the gene. Mutations in a dyad symmetry element centered at position -66 and in a repeat of the downstream arm of the dyad symmetry at position -27 cause derepressed citB expression. In this work, a protein able to bind to a DNA fragment containing these elements was purified and identified. This protein, named CcpC (Catabolite control protein C), shares sequence similarity with members of the LysR family of transcriptional regulators. In addition to binding to the citB promoter, CcpC bound to the promoter of the citZ gene, which encodes the cell's major citrate synthase and is subject to carbon catabolite repression. In a ccpC null mutant, expression of both citB and citZ was derepressed in glucose-glutamine minimal medium, indicating that CcpC is a negative regulator of citB and citZ gene expression. DNase I footprinting experiments showed that CcpC binds to two sites within the citB promoter region, corresponding to the dyad symmetry and -27 elements. In the presence of citrate, a putative inducer, only the dyad symmetry element was fully protected by CcpC. When the dyad symmetry element was mutated, CcpC was no longer able to bind to either the dyad symmetry or -27 elements. Repression of citB and citZ gene expression during anaerobiosis also proved to be mediated by CcpC.
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Affiliation(s)
- C Jourlin-Castelli
- Department of Molecular Biology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA, 02111, USA
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Abstract
Vascular endothelial growth factor is a highly conserved, heparin-binding protein which mediates a number of critical developmental processes in both vertebrates and invertebrates, including angiogenesis, vasculogenesis and hematopoiesis. We employed an organotypic rat explant model (produced from embryonic day 17 fetuses) to assess the effects of vascular endothelial growth factor on brain microvasculature in general and the ventral midbrain specifically. Immunohistochemistry using antisera to rat endothelial cell antigen and laminin demonstrated a robust, dose-dependent effect of vascular endothelial growth factor, resulting in increased vessel neogenesis, branching and lumen size by three days in vitro. This effect was blocked by addition of an anti-vascular endothelial growth factor antibody. At higher doses of vascular endothelial growth factor, the effect was attenuated, though a statistically significant increase in both astrocyte, and neuronal density was observed using antisera to glial and neuronal markers. Tyrosine hydroxylase-immunoreactive (i.e. dopaminergic) neurons, particularly, exhibited increased survival in response to vascular endothelial growth factor application. Vascular endothelial growth factor had a mitogenic effect on endothelial cells and astrocytes, but not dopaminergic neurons, as demonstrated by the addition of [3H]thymidine to the cultures 2 h after the cultures were established. Similarly, results of a radioreceptor assay indicated that specific vascular endothelial growth factor binding sites were present on blood vessels and astrocytes, and were up-regulated by exposure to vascular endothelial growth factor. We conclude that, in explants of the ventral mesencephalon, exogenously applied vascular endothelial growth factor is mitogenic for endothelial cells and astrocytes, and promotes growth/survival of neurons in general and dopaminergic neurons in particular.
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Affiliation(s)
- W F Silverman
- Department of Morphology, Zlotowski Center of Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
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Rosenstein JM, Mani N, Silverman WF, Krum JM. Patterns of brain angiogenesis after vascular endothelial growth factor administration in vitro and in vivo. Proc Natl Acad Sci U S A 1998; 95:7086-91. [PMID: 9618543 PMCID: PMC22748 DOI: 10.1073/pnas.95.12.7086] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.3] [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] [Indexed: 02/07/2023] Open
Abstract
Vascular endothelial growth factor (VEGF) is a secreted endothelial cell mitogen that has been shown to induce vasculogenesis and angiogenesis in many organ systems and tumors. Considering the importance of VEGF to embryonic vascularization and survival, the effects of administered VEGF on developing or adult cerebrovasculature are unknown: can VEGF alter brain angiogenesis or mature cerebrovascular patterns? To examine these questions we exposed fetal, newborn, and adult rat cortical slice explants to graduated doses of recombinant VEGF. The effects of another known angiogenic factor, basic fibroblast growth factor (bFGF), were evaluated in a comparable manner. In addition, we infused VEGF via minipump into the adult cortex. Significant angiogenic effects were found in all VEGF experiments in a dose-responsive manner that were abolished by the addition of VEGF neutralizing antibody. Fetal and newborn explants had a highly complex network of branched vessels that immunoexpressed the flt-1 VEGF receptor, and flk-1 VEGF receptor expression was determined by reverse transcription-PCR. Adult explants had enlarged, dilated vessels that appeared to be an expansion of the existing network. All bFGF-treated explants had substantially fewer vascular profiles. VEGF infusions produced both a remarkable localized neovascularization and, unexpectedly, the expression of flt-1 on reactive astrocytes but not on endothelial cells. The preponderance of neovascularization in vitro and in vivo, however, lacked the blood-brain barrier (BBB) phenotype marker, GLUT-1, suggesting that in brain the angiogenic role of VEGF may differ from a potential BBB functional role, i.e., transport and permeability. VEGF may serve an important capacity in neovascularization or BBB alterations after brain injury.
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Affiliation(s)
- J M Rosenstein
- Department of Anatomy and Cell Biology, The George Washington University Medical Center, Washington, DC 20037, USA
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Mani N, Sancheti P, Jiang ZD, McNaney C, DeCenzo M, Knight B, Stankis M, Kuranda M, Rothstein DM, Sanchet P, Knighti B. Screening systems for detecting inhibitors of cell wall transglycosylation in Enterococcus. Cell wall transglycosylation inhibitors in Enterococcus. J Antibiot (Tokyo) 1998; 51:471-9. [PMID: 9666175 DOI: 10.7164/antibiotics.51.471] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [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: 11/21/2022]
Abstract
We devised two screening systems to detect cell wall transglycosylation inhibitors. One screen utilizes a mutant of Enterococcus faecalis strain A256 that is dependent on vancomycin or moenomycin for growth. In the absence of transglycosylation inhibitors the strain fails to grow, while in the presence of inhibitors, cells are rescued. A second screening organism E. faecalis strain MDD212 utilizes a translational fusion of the lacZ gene to the vanH promoter in a derivative of E. faecalis that contains a vancomycin resistance determinant. Induction of beta-galactosidase occurs when cells are exposed to inhibitors of transglycosylation. Our natural products drug source of fungal fermentations was tested with these screens. Several cultures that produced the same family of compounds, called the thielavins, were detected. Thielavin B inhibited the formation of peptidoglycan in an in vitro assay, suggesting that these screening systems can detect compounds that interfere with cell wall transglycosylation.
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Affiliation(s)
- N Mani
- Drug discovery department, Millennium Pharmaceuticals, Cambridge, MA 02139, USA
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Abstract
The present study examined the development of calcium binding protein-containing neurons in a timed series of fetal neocortical transplants. The immunoexpression of parvalbumin and calbindin, which are subpopulations of GABAergic neurons, have been widely studied in normal development and in disease and injury states. Because of their purported resistance to oxidative injury by their ability to buffer Ca++ influx, these neurons have been particularly studied following ischemia. Because it is likely that oxidative stress is associated with the grafting procedure, we sought to determine if these neurons displayed enhanced survival characteristics. Normally, parvalbumin and calbindin represent about 5-10% of cortical neurons. Within 2-4 wk after grafting the expression of both proteins increased markedly in that a relatively larger number of neurons (27% for parvalbumin) were immunopositive. This increase was transitory, however, and by 4 mo and beyond, confocal microscopic data showed a reduction of over 50% of parvalbumin (+) neurons and processes. Calbindin (+) processes showed a qualitative change in that they were smaller with less terminal branching. Electron microscopy confirmed a substantial reduction in parvalbumin synaptic contacts. Interestingly, in older grafts, remaining parvalbumin neurons were those that were strongly NSE (+) suggesting a link between normal metabolism and Ca++ buffering in grafted neurons. It is possible that in early grafts certain neuronal populations transiently upregulated calcium binding proteins as a defensive mechanism against Ca++ influx associated with oxidative stress. Over time, however, following physiological normalization within grafts, the calcium binding protein (+) neurons are diminished, possibly due to lack of appropriate afferent input to the interneuronal pool.
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Affiliation(s)
- J M Rosenstein
- Department of Anatomy and Cell Biology, The George Washington University Medical Center, Washington, DC 20027, USA
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Silverman W, Krum J, Mani N, Rosenstein J. Vascular endothelial growth factor (VEGF) induces proliferation of astrocytes and promotes survival of dopaminergic neurons in mesencephalic explants. Neurosci Lett 1997. [DOI: 10.1016/s0304-3940(97)90194-4] [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: 10/26/2022]
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Abstract
Nucleotide sequencing of a 3779-bp fragment of the Staphylococcus aureus bacteriophage 80 alpha revealed two open reading frames: ORF1, designated as lytA, which encodes a polypeptide of 481 amino acids with an apparent M(r) of 53.81 kDa; and ORF2, designated as holin, which encodes for a hydrophobic polypeptide of 145 amino acids with an apparent M(r) of 15.58 kDa and exhibits two putative transmembrane helices. Both genes showed 100% sequence homology to that of the peptidoglycan hydrolase and holin genes of the S. aureus phage phi 11 reported earlier. In addition, the downstream sequences of the lytA gene were homologous to the phage attachment site (attP) of the phage phi 11. Based on our data we propose that the lytic system of the phage 80 alpha evolved from that of phage phi 11.
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Affiliation(s)
- J Bon
- Department of Biological Sciences, Illinois State University, Normal 61790-4120, USA
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