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1.
Biochem Biophys Res Commun ; 460(2): 302-7, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25791476

RESUMO

Poly-N-acetyl-lactosamine (polyLacNAc) on N-glycans facilitate lung specific metastasis of melanoma cells by serving as high affinity ligands for galectin-3, expressed in highest amounts in the lungs, on almost all its tissue compartments including on the surface of vascular endothelium. PolyLacNAc not only aids in initial arrest on the organ endothelium but in all the events of extravasation. Inhibition of polyLacNAc synthesis, or competitive inhibition of its interaction with galectin-3 all inhibited these processes and experimental metastasis. Transgenic galectin-3 mice, viz., gal-3(+/+) (wild type), gal-3(+/-) (hemizygous) and gal-3(-/-) (null) have been used to prove that galectin-3/polyLacNAc interactions are indeed critical for lung specific metastasis. Gal-3(+/-) mice which showed <50% expression of galectin-3 on the lungs also showed proportionate decrease in the number of B16F10 melanoma metastatic colonies affirming that galectin-3 and polyLacNAc interactions are indeed key determinants of lung metastasis. However, surprisingly, the number and size of metastatic colonies in gal-3(-/-) mice was very similar as that seen in gal-3(+/+) mice. The levels of lactose binding lectins on the lungs and the transcripts of other galectins (galectin-1, -8 and -9) which are expressed on lungs and have similar sugar binding specificities as galectins-3, remain unchanged in gal-3(+/+) and gal-3(-/-) mice. Further, inhibition of N-glycosylation with Swainsonine (SW) which drastically reduces metastasis of B16F10 cells in gal-3(+/+) mice, did not affect lung metastasis when assessed in gal-3(-/-) mice. Together, these results rule out the possibility of some other galectin taking over the function of galectin-3 in gal-3(-/-) mice. Chimeric mice generated to assess if absence of any effect on metastasis is due to compromised tumor immunity by replacing bone marrow of gal-3(-/-) mice with that from gal-3(+/+) mice, also failed to impact melanoma metastasis. As galectin-3 regulates several immune functions including maturation of different immune cells, compromised tumor immunity could be the major determinant of melanoma metastasis in gal-3(-/-) mice and warrants thorough investigation.


Assuntos
Galectina 3/fisiologia , Metástase Neoplásica , Polissacarídeos/fisiologia , Animais , Sequência de Bases , Linhagem Celular Tumoral , Primers do DNA , Galectina 3/genética , Neoplasias Pulmonares/secundário , Melanoma Experimental/patologia , Camundongos , Camundongos Transgênicos , Reação em Cadeia da Polimerase
2.
J Immunol ; 191(5): 2412-25, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-23926324

RESUMO

Peripheral tissue homing receptors enable T cells to access inflamed nonlymphoid tissues. In this study, we show that two such molecules, E-selectin ligand and α4ß1 integrin, enable activated and memory T cells to enter lymph nodes (LN) as well. This affects the quantitative and qualitative distribution of these cells among regional LN beds. CD8 memory T cells in LN that express these molecules were mostly CD62L(lo) and would normally be classified as effector memory cells. However, similar to central memory cells, they expanded upon Ag re-encounter. This led to differences in the magnitude of the recall response that depended on the route of immunization. These novel cells share properties of both central and effector memory cells and reside in LN based on previously undescribed mechanisms of entry.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Quimiotaxia de Leucócito/imunologia , Memória Imunológica/imunologia , Linfonodos/citologia , Transferência Adotiva , Animais , Linfócitos T CD8-Positivos/citologia , Linfonodos/imunologia , Camundongos , Camundongos Endogâmicos C57BL
3.
Process Biochem ; 129: 241-256, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37013198

RESUMO

One of the outcomes from the global COVID-19 pandemic caused by SARS-CoV-2 has been an acceleration of development timelines to provide treatments in a timely manner. For example, it has recently been demonstrated that the development of monoclonal antibody therapeutics from vector construction to IND submission can be achieved in five to six months rather than the traditional ten-to-twelve-month timeline using CHO cells [1], [2]. This timeline is predicated on leveraging existing, robust platforms for upstream and downstream processes, analytical methods, and formulation. These platforms also reduce; the requirement for ancillary studies such as cell line stability, or long-term product stability studies. Timeline duration was further reduced by employing a transient cell line for early material supply and using a stable cell pool to manufacture toxicology study materials. The development of non-antibody biologics utilizing traditional biomanufacturing processes in CHO cells within a similar timeline presents additional challenges, such as the lack of platform processes and additional analytical assay development. In this manuscript, we describe the rapid development of a robust and reproducible process for a two-component self-assembling protein nanoparticle vaccine for SARS-CoV-2. Our work has demonstrated a successful academia-industry partnership model that responded to the COVID-19 global pandemic quickly and efficiently and could improve our preparedness for future pandemic threats.

4.
J Am Soc Mass Spectrom ; 33(11): 2191-2198, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36206542

RESUMO

Reversed-phase liquid chromatographic mass spectrometry (rpLC-MS) is a universal, platformed, and essential analytical technique within pharmaceutical and biopharmaceutical research. Typical rpLC method gradient times can range from 5 to 20 min. As monoclonal antibody (mAb) therapies continue to evolve and bispecific antibodies (BsAbs) become more established, research stage engineering panels will clearly evolve in size. Therefore, high-throughput (HT) MS and automated deconvolution methods are key for success. Additionally, newer therapeutics such as bispecific T-cell engagers and nucleic acid-based modalities will also require MS characterization. Herein, we present a modality and target agnostic HT solid-phase extraction (SPE) MS method that affords the analysis of a 96-well plate in 41.4 min, compared to the traditional rpLC-MS method that would typically take 14.4 h. The described method can accurately determine the molecular weights for monodispersed and highly polydispersed biotherapeutic species and membrane proteins; determine levels of glycosylation, glycation, and formylation; detect levels of chain mispairing; and determine accurate drug-to-antibody ratio values.


Assuntos
Cromatografia de Fase Reversa , Extração em Fase Sólida , Espectrometria de Massas/métodos , Cromatografia de Fase Reversa/métodos , Peso Molecular , Anticorpos Monoclonais/química
5.
Biochemistry ; 50(17): 3495-501, 2011 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-21476509

RESUMO

The phylloquinones of photosystem I (PS I), A(1A) and A(1B), exist in near-equivalent protein environments but possess distinct thermodynamic and kinetic properties. Although the determinants responsible for the different properties of the phylloquinones are not completely understood, the strength and geometry of hydrogen bond interactions are significant factors in tuning and control of function. This study focuses on characterizing the hydrogen-bonding interactions of the phylloquinone acceptor, A(1A), by (1)H and (14)N HYSCORE spectroscopy. Photoaccumulation of PS I complexes at pH 8.0 results in the trapping of the phyllosemiquinone anion, A(1A)(-), on the A-branch of cofactors. The experiments described here indicate that A(1A)(-) forms a single H-bond. Using a simple point dipole approximation, we estimate its length to be 1.6 ± 0.1 Å. The value of the (1)H isotropic hyperfine coupling constant suggests that the H-bond has significant out-of-plane character. The (14)N HYSCORE spectroscopy experiments support the assignment of a H-bond wherein, the (14)N quadrupolar coupling constant is consistent with a backbone amide nitrogen as the hydrogen bond donor.


Assuntos
Benzoquinonas/química , Modelos Moleculares , Complexo de Proteína do Fotossistema I/química , Vitamina K 1/análogos & derivados , Vitamina K 1/química , Espectroscopia de Ressonância de Spin Eletrônica , Ligação de Hidrogênio , Oxirredução
6.
Biochim Biophys Acta ; 1787(9): 1057-88, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19409369

RESUMO

This review focuses on phylloquinone as an indispensable link between light-induced charge separation and subsequent charge stabilization in Photosystem I (PS I). Here, the role of the polypeptide in conferring the necessary kinetic and thermodynamic properties to phylloquinone so as to specify its functional role in PS I electron transfer is discussed. Photosynthetic electron transfer and the role of quinones in Type I and Type II reaction centers are introduced at the outset with particular emphasis on the determination of redox potentials of the cofactors. Currently used methodologies, particularly time-resolved optical spectroscopy and varieties of magnetic resonance spectroscopy that have become invaluable in uncovering the details of phylloquinone function are described in depth. Recent studies on the selective alteration of the protein environment and on the incorporation of foreign quinones either by chemical or genetic means are explored to assess how these studies have improved our understanding of protein-quinone interactions. Particular attention is paid to the function of the H-bond, methyl group and phytyl tail of the phylloquinone in interacting with the protein environment.


Assuntos
Transporte de Elétrons/fisiologia , Complexo de Proteína do Fotossistema I/metabolismo , Vitamina K 1/metabolismo , Modelos Biológicos , Oxirredução , Vitamina K 1/química
7.
Biochemistry ; 48(15): 3315-24, 2009 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-19249875

RESUMO

Photosystem I (PS I) contains two molecules of phylloquinone that function as electron transfer cofactors at highly reducing midpoint potentials. It is therefore surprising that each phylloquinone is hydrogen bonded at the C(4) position to the backbone -NH of a Leu residue since this serves to drive the midpoint potential more oxidizing. To better understand the role of the H-bond, a PS I variant was generated in which L722(PsaA) was replaced with a bulky Trp residue. This change was designed to alter the conformation of the A-jk(1) loop and therefore change the strength of the H-bond to the PsaA-branch phylloquinone. Transient EPR studies at 80 K show that the A(1A) site in the PS I variant is fully occupied with phylloquinone, but the absence of methyl hyperfine couplings in the quinone contribution to the P(700)(*+)A(1)(*-) radical pair spectrum indicates that the H-bond has been weakened. In wild-type PS I, reduction of F(A) and F(B) with sodium dithionite causes a approximately 30% increase in the amplitude of the P(700)(*+)A(1)(*-) transient EPR signal due to the added contribution of the PsaB-branch cofactors to low temperature reversible electron transfer between P(700) and A(1A). In contrast, the same treatment to the L722W(PsaA) variant leads to a approximately 75% reduction in the amplitude of the P(700)(*+)A(1)(*-) transient EPR signal. This behavior suggests that A(1A) has undergone double reduction to phyllohydroquinone, thereby preventing electron transfer past A(0A). The remaining 25% of the P(700)(*+)A(1)(*-) radical pair spectrum shows an altered spin polarization pattern and pronounced methyl hyperfine couplings characteristic of asymmetric H-bonding to the phylloquinone. Numerical simulations of the polarization pattern indicate that it arises primarily from electron transfer between P(700) and A(1B). The altered reduction behavior in the L722W(PsaA) variant suggests that the primary purpose of the H-bond is to tie up the C(4) carbonyl group of phylloquinone in a H-bond so as to prevent protonation and hence lower the probability of double reduction during periods of high light intensity.


Assuntos
Leucina/química , Complexo de Proteína do Fotossistema I/química , Synechocystis/química , Vitamina K 1/química , Substituição de Aminoácidos/genética , Cristalografia por Raios X , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/química , Ligação de Hidrogênio , Leucina/genética , Oxirredução , Complexo de Proteína do Fotossistema I/genética , Complexo de Proteína do Fotossistema I/fisiologia , Mutação Puntual , Synechocystis/genética , Synechocystis/fisiologia , Temperatura , Triptofano/genética , Vitamina K 1/metabolismo
8.
Glycoconj J ; 26(4): 445-56, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-18949555

RESUMO

Galectin-3 on vascular endothelium has been shown to facilitate lung specific metastasis. Metastatic variants of B16 melanoma were chosen to identify specific ligands that mediate lung colonization via galectin-3. Flow cytometry showed that, galectin-3 binding to cells correlates with surface expression of poly N-acetyllactosamine (polylacNAc) but not with other reported ligands, e.g. Thomsen-Friedenreich (T/Tn) antigen. Immobilized galectin-3 promoted adhesion of melanoma cells in a metastasis dependent manner. Moreover, adhesion and galectin-3 binding to cells were specifically inhibited with lactose. These properties together with lung metastasis were inhibited with N-glycosylation inhibitor Swainsonine (SW), whereas, O-glycosylation inhibitor Benzyl-alpha-N-acetylgalactosamine (BG) had no effect. BG treatment significantly increased expression of T/Tn antigen on low metastatic cells; however, had no effect on their metastatic potential. The studies very comprehensively demonstrate the importance of polylacNAc substitutions on N-oligosaccharides in galectin-3 mediated lung metastasis.


Assuntos
Antígenos Glicosídicos Associados a Tumores/metabolismo , Galectina 3/metabolismo , Neoplasias Pulmonares/secundário , Melanoma/metabolismo , Melanoma/patologia , Oligossacarídeos/metabolismo , Polissacarídeos/metabolismo , Acetilgalactosamina/análogos & derivados , Acetilgalactosamina/farmacologia , Animais , Compostos de Benzil/farmacologia , Biotinilação/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Citometria de Fluxo , Humanos , Proteínas Imobilizadas , Camundongos , Oligossacarídeos/química , Especificidade de Órgãos/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos
9.
J Cancer Res Clin Oncol ; 141(9): 1563-74, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25614122

RESUMO

PURPOSE: Expression of lysosome-associated membrane protein-1 (LAMP1) on the surface correlates with metastatic potential of B16 melanoma cells. Downregulation of their expression in high metastatic (B16F10) cells reduced their surface expression and metastatic potential. Present investigations explore if overexpression of LAMP1 on the surface of low metastatic (B16F1) cells augment their metastatic ability, and if so, how? METHODS: B16F1 cells were transduced with lentiviral vector carrying mutant-LAMP1 (Y386A) (mutLAMP1). Surface expression of LAMP1 and carbohydrates was analyzed by flow cytometry, immunofluorescence and/or immunoprecipitation and Western blotting. Cell spreading and motility were assessed on components of extracellular matrix (ECM) (fibronectin) and basement membrane (BM) (matrigel), and galectin-3-coated coverslips/plates. Metastatic potential was assessed using experimental metastasis assay. RESULTS: Pre-incubation with anti-LAMP1 antibodies significantly reduced lung metastasis of B16F10 cells. Overexpression of mutLAMP1 significantly increased its surface expression on B16F1 cells, resulting in increased cellular spreading and motility on fibronectin and matrigel. LAMP1 is the major carrier of poly-N-acetyllactosamine (polyLacNAc) on B16F10 cells. However, significantly higher expression of mutLAMP1 had no effect on galectin-3 binding on cell surface or on spreading or motility of cells on galectin-3-coated coverslips/plates. These cells also failed to show any gain in metastatic ability. This could be because LAMP1 from these cells carried significantly lower levels of polyLacNAc in comparison with B16F10 cells. CONCLUSIONS: PolyLacNAc on B16F10 cells and galectin-3 on lungs are the major participants in melanoma metastasis. Although surface LAMP1 promotes interactions with organ ECM and BM, carbohydrates on LAMP1 play a decisive role in dictating lung metastasis.


Assuntos
Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Proteínas de Membrana Lisossomal/metabolismo , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Animais , Metabolismo dos Carboidratos , Movimento Celular/fisiologia , Feminino , Galectina 3/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Células Tumorais Cultivadas
10.
Nat Commun ; 5: 5145, 2014 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-25312006

RESUMO

Grafting polymers onto surfaces at high density to yield polymer brush coatings is a widely employed strategy to reduce biofouling and interfacial friction. These brushes almost universally feature synthetic polymers, which are often heterogeneous and do not readily allow incorporation of chemical functionalities at precise sites along the constituent chains. To complement these synthetic systems, we introduce a biomimetic, recombinant intrinsically disordered protein that can assemble into an environment-sensitive brush. This macromolecule adopts an extended conformation and can be grafted to solid supports to form oriented protein brushes that swell and collapse dramatically with changes in solution pH and ionic strength. We illustrate the value of sequence specificity by using proteases with mutually orthogonal recognition sites to modulate brush height in situ to predictable values. This study demonstrates that stimuli-responsive brushes can be fabricated from proteins and introduces them as a new class of smart biomaterial building blocks.


Assuntos
Proteínas Intrinsicamente Desordenadas/química , Proteínas de Neurofilamentos/química , Polímeros/química , Animais , Biomimética , Proteínas de Neurofilamentos/genética , Ratos , Propriedades de Superfície
11.
Clin Exp Metastasis ; 31(6): 661-73, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24952269

RESUMO

Interactions between molecules on the surface of tumor cells and those on the target organ endothelium play an important role in their arrest in an organ. Galectin-3 on the lung endothelium and high affinity ligands poly-N-acetyllactosamine (polyLacNAc) on N-oligosaccharides on melanoma cells facilitate such interactions. However, to extravasate and colonize an organ the cells must stabilize these interactions by spreading to retract endothelium, degrade exposed basement membrane (BM) and move into parenchyma and proliferate. Here, we show that galectin-3 is expressed on all the major compartments of the lungs and participates in not just promoting adhesion but also in spreading. We for the first time demonstrate that both soluble and immobilized galectin-3 induce secretion of MMP-9 required to breach vascular BM. Further, we show that immobilized galectin-3 is used as traction for the movement of cells. Downregulation of galactosyltransferases-I and -V resulted in significant loss in expression of polyLacNAc and thus reduced binding of galectin-3. This was accompanied with a loss in adhesion, spreading, MMP-9 secretion and motility of the cells on galectin-3 and thus their metastasis to lungs. Metastasis could also be inhibited by blocking surface polyLacNAc by pre-incubating cells with truncated galectin-3 (which lacked oligomerization domain) or by feeding mice with modified citrus pectin in drinking water. Overall, these results unequivocally show that polyLacNAc on melanoma cells and galectin-3 on the lungs play a critical role in arrest and extravasation of cells in the lungs and strategies that target these interactions inhibit lung metastasis.


Assuntos
Galectina 3/metabolismo , Pulmão/metabolismo , Melanoma Experimental/patologia , Animais , Sequência de Bases , Western Blotting , Adesão Celular , Linhagem Celular Tumoral , Primers do DNA , Citometria de Fluxo , Ligantes , Pulmão/patologia , Camundongos , Reação em Cadeia da Polimerase em Tempo Real
12.
Artigo em Inglês | MEDLINE | ID: mdl-22231983

RESUMO

Proteins possess a number of attractive properties that have contributed to their recent emergence as nanoscale building blocks for biomaterials and bioinspired materials. For instance, the amino acid sequence of a protein can be precisely controlled and manipulated via recombinant DNA technology, and proteins can be biosynthesized with very high purity and virtually perfect monodispersity. Most importantly, protein-based biomaterials offer the possibility of technologically harnessing the vast array of functions that these biopolymers serve in nature. In this review, we discuss recent progress in the field of protein-based biomaterials, with an overall theme of relating protein structure to material properties. We begin by discussing materials based on proteins that have well-defined three-dimensional structures, focusing specifically on elastin- and silk-like peptides. We then explore the newer field of materials based on intrinsically disordered proteins, using nucleoporin and neurofilament proteins as case studies. A key theme throughout the review is that specific environmental stimuli can trigger protein conformational changes, which in turn can alter macroscopic material properties and function.


Assuntos
Nanoestruturas/química , Dobramento de Proteína , Proteínas/química , Proteínas/metabolismo , Materiais Biocompatíveis/química , Humanos
13.
J Phys Chem B ; 115(8): 1751-9, 2011 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-21299208

RESUMO

In Photosystem I, the backbone nitrogen of Leu722(PsaA) forms a hydro-gen bond with the C(4) carbonyl oxygen of phylloquinone in the A(1A) site. A previous low-temperature EPR study indicated that substitution of Leu722(PsaA) with a bulky Trp residue results in a weakened H-bond. Here, we employ room temperature, time-resolved optical spectroscopy and variable temperature, transient EPR spectroscopy to probe the effect of the altered H-bond on the energetics and kinetics of electron transfer. Relative to the wild type, we find that the rate of electron transfer from A(1A)(-) to F(X) in the L722W(PsaA) variant is faster by a factor of 3. This change is attributed to a lowered midpoint potential of A(1A)/A(1A)(-), resulting in a larger Gibbs free energy change between A(1A)/A(1A)(-) and F(X)/F(X)(-). An activation energy of 180±10 meV is determined for the A(1A)(-)-to-F(X) forward electron transfer step in the L722W(PsaA) variant compared with 220±10 meV in the wild type. The Arrhenius plot shows a break at ∼200 K, below which the rate becomes nearly independent of temperature. This behavior is described using a quantum mechanical treatment that takes the zero-point energy into account as well as an alternative model that invokes a dynamical transition in the protein at ∼200 K.


Assuntos
Complexo de Proteína do Fotossistema I/química , Vitamina K 1/química , Substituição de Aminoácidos , Espectroscopia de Ressonância de Spin Eletrônica , Transporte de Elétrons , Ligação de Hidrogênio , Cinética , Mutação , Complexo de Proteína do Fotossistema I/genética , Complexo de Proteína do Fotossistema I/metabolismo , Teoria Quântica , Temperatura , Termodinâmica
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