1
|
Zhu M, Ma L, Zhong P, Huang J, Gai J, Li G, Li Y, Qiao P, Gu H, Li X, Yin Y, Zhang L, Deng Z, Sun B, Chen Z, Ding Y, Wan Y. A novel inhalable nanobody targeting IL-4Rα for the treatment of asthma. J Allergy Clin Immunol 2024:S0091-6749(24)00573-6. [PMID: 38871183 DOI: 10.1016/j.jaci.2024.05.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 05/27/2024] [Accepted: 05/31/2024] [Indexed: 06/15/2024]
Abstract
BACKGROUND Inhalable biologics represent a promising approach to improve the efficacy and safety of asthma treatment. Although several mAbs targeting IL-4 receptor α chain (IL-4Rα) have been approved or are undergoing clinical trials, the development of inhalable mAbs targeting IL-4Rα presents significant challenges. OBJECTIVE Capitalizing on the distinctive advantages of nanobodies (Nbs) in maintaining efficacy during storage and administration, we sought to develop a novel inhalable IL-4Rα Nb for effectively treating asthma. METHODS Three IL-4Rα immunized Nb libraries were used to generate specific and functional IL-4Rα Nbs. LQ036, a bivalent Nb comprising 2 HuNb103 units, was constructed with a high affinity and specificity for human IL-4Rα. The efficacy, pharmacokinetics, and safety of inhaled LQ036 were evaluated in B-hIL4/hIL4RA humanized mice. RESULTS LQ036 inhibited secreted embryonic alkaline phosphatase reporter activity, inhibited TF-1 cell proliferation, and suppressed phosphorylated signal transducer and activator of transduction 6 in T cells from patients with asthma. Crystal structure analysis revealed a binding region similar to dupilumab but with higher affinity, leading to better efficacy in blocking the signaling pathway. HuNb103 competed with IL-4 and IL-13 for IL-4Rα binding. Additionally, LQ036 significantly inhibited ovalbumin-specific IgE levels in serum, CCL17 levels in bronchoalveolar lavage fluid, bronchial mucous cell hyperplasia, and airway goblet cell hyperplasia in B-hIL4/hIL4RA humanized mice. Inhaled LQ036 exhibited favorable pharmacokinetics, safety, and tissue distribution, with higher concentrations observed in the lungs and bronchi. CONCLUSIONS These findings from preclinical studies establish the safety and efficacy of inhaled LQ036, underscoring its potential as a pioneering inhalable biologic therapy for asthma.
Collapse
Affiliation(s)
- Min Zhu
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China
| | - Linlin Ma
- School of Medical Technology, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Peiyu Zhong
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Jing Huang
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China
| | - Junwei Gai
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China
| | - Guanghui Li
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China
| | - Yanfei Li
- School of Medical Technology, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Peng Qiao
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China
| | - Huaiyu Gu
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China
| | - Xiaofei Li
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China
| | - Yong Yin
- Department of Respiratory Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Children's Medical Center Pediatric Medical Complex (Pudong), Shanghai, China; Pediatric AI Clinical Application and Research Center, Shanghai Children's Medical Center, Shanghai, China
| | - Lei Zhang
- Department of Respiratory Medicine, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhenzhen Deng
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China
| | - Baihe Sun
- School of Medical Technology, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Zhihong Chen
- Department of Respiratory and Critical Care Medicine of Zhongshan Hospital, Shanghai Institute of Respiratory Disease, Fudan University, Shanghai, China.
| | - Yu Ding
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China.
| | - Yakun Wan
- Shanghai Novamab Biopharmaceuticals Co, Ltd, Shanghai, China.
| |
Collapse
|
2
|
Zhu L, Sun L, Zhang Y, Liu X, Li X, Zhou Z, Cui Y, Zhou CX, Li TJ. PON3::LCN1 and HTN3::MSANTD3 Gene Fusions With NR4A3/NR4A2 Expression in Salivary Acinic Cell Carcinoma. Am J Surg Pathol 2024; 48:681-690. [PMID: 38682454 DOI: 10.1097/pas.0000000000002219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Acinic cell carcinoma of the salivary gland (AciCC) is a low-grade carcinoma characterized by the overexpression of the transcription factor nuclear receptor subfamily 4 group A member 3 (NR4A3). AciCC has been the subject of a few molecular research projects. This study delves into AciCC's molecular landscape to identify additional alterations and explore their clinical implications. RNA sequencing and immunohistochemical staining for markers NR4A3/NR4A2, DOG-1, S100, and mammaglobin were utilized on 41 AciCCs and 11 secretory carcinoma (SC) samples. NR4A3 was evident in 35 AciCCs, while the residual 6 were NR4A3-negative and NR4A2-positive; SC samples were consistently NR4A3-negative. A novel fusion, PON3 exon 1- LCN1 exon 5, was detected in 9/41 (21.9%) AciCCs, exhibiting a classical histologic pattern with serous cell components growing in solid sheets alongside the intercalated duct-like component. Clinical follow-up of 39 patients over a median of 59 months revealed diverse prognostic outcomes: 34 patients exhibited no disease evidence, whereas the remaining 5 experienced poorer prognosis, involving local recurrence, lymph node, and distant metastasis, and disease-associated death, 4 of which harbored the PON3::LCN1 fusion. In addition, the HTN3::MSANTD3 fusion was recurrently identified in 7/41 AciCC cases. SC patients lacked both fusions. Immunohistochemistry uncovered differential expression of DOG-1, S100, and mammaglobin across samples, providing nuanced insights into their roles in AciCC. This study accentuates PON3::LCN1 and HTN3::MSANTD3 fusions as recurrent molecular events in AciCC, offering potential diagnostic and prognostic utility and propelling further research into targeted therapeutic strategies.
Collapse
MESH Headings
- Humans
- Male
- Carcinoma, Acinar Cell/genetics
- Carcinoma, Acinar Cell/pathology
- Female
- Salivary Gland Neoplasms/genetics
- Salivary Gland Neoplasms/pathology
- Salivary Gland Neoplasms/mortality
- Salivary Gland Neoplasms/metabolism
- Salivary Gland Neoplasms/chemistry
- Middle Aged
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/analysis
- Adult
- Aged
- Nuclear Receptor Subfamily 4, Group A, Member 2/genetics
- Nuclear Receptor Subfamily 4, Group A, Member 2/analysis
- Receptors, Steroid/genetics
- Receptors, Steroid/metabolism
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/analysis
- Receptors, Thyroid Hormone/metabolism
- Young Adult
- Gene Fusion
- Aged, 80 and over
- DNA-Binding Proteins/genetics
- Oncogene Proteins, Fusion/genetics
- Immunohistochemistry
Collapse
Affiliation(s)
- Lijing Zhu
- Department of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, China
- National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing, China
- Research Unit of Precision Pathologic Diagnosis in Tumors of the Oral and Maxillofacial Regions, Chinese Academy of Medical Sciences (2019RU034), Beijing, China
| | - Lisha Sun
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ye Zhang
- Department of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, China
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoxiao Liu
- Central laboratory, Peking University School and Hospital of Stomatology, Beijing, China
| | - XueFen Li
- Research Unit of Precision Pathologic Diagnosis in Tumors of the Oral and Maxillofacial Regions, Chinese Academy of Medical Sciences (2019RU034), Beijing, China
| | - Zheng Zhou
- Department of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, China
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yajuan Cui
- Department of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, China
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chuan-Xiang Zhou
- Department of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, China
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tie-Jun Li
- Department of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, China
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
3
|
Glasgow BJ. Tear Lipocalin and Lipocalin-Interacting Membrane Receptor. Front Physiol 2021; 12:684211. [PMID: 34489718 PMCID: PMC8417070 DOI: 10.3389/fphys.2021.684211] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/13/2021] [Indexed: 11/24/2022] Open
Abstract
Tear lipocalin is a primate protein that was recognized as a lipocalin from the homology of the primary sequence. The protein is most concentrated in tears and produced by lacrimal glands. Tear lipocalin is also produced in the tongue, pituitary, prostate, and the tracheobronchial tree. Tear lipocalin has been assigned a multitude of functions. The functions of tear lipocalin are inexorably linked to structural characteristics that are often shared by the lipocalin family. These characteristics result in the binding and or transport of a wide range of small hydrophobic molecules. The cavity of tear lipocalin is formed by eight strands (A-H) that are arranged in a β-barrel and are joined by loops between the β-strands. Recently, studies of the solution structure of tear lipocalin have unveiled new structural features such as cation-π interactions, which are extant throughout the lipocalin family. Lipocalin has many unique features that affect ligand specificity. These include a capacious and a flexible cavity with mobile and short overhanging loops. Specific features that confer promiscuity for ligand binding in tear lipocalin will be analyzed. The functions of tear lipocalin include the following: antimicrobial activities, scavenger of toxic and tear disruptive compounds, endonuclease activity, and inhibition of cysteine proteases. In addition, tear lipocalin binds and may modulate lipids in the tears. Such actions support roles as an acceptor for phospholipid transfer protein, heteropolymer formation to alter viscosity, and tear surface interactions. The promiscuous lipid-binding properties of tear lipocalin have created opportunities for its use as a drug carrier. Mutant analogs have been created to bind other molecules such as vascular endothelial growth factor for medicinal use. Tear lipocalin has been touted as a useful biomarker for several diseases including breast cancer, chronic obstructive pulmonary disease, diabetic retinopathy, and keratoconus. The functional possibilities of tear lipocalin dramatically expanded when a putative receptor, lipocalin-interacting membrane receptor was identified. However, opposing studies claim that lipocalin-interacting membrane receptor is not specific for lipocalin. A recent study even suggests a different function for the membrane protein. This controversy will be reviewed in light of gene expression data, which suggest that tear lipocalin has a different tissue distribution than the putative receptor. But the data show lipocalin-interacting membrane receptor is expressed on ocular surface epithelium and that a receptor function here would be rational.
Collapse
Affiliation(s)
- Ben J. Glasgow
- Departments of Ophthalmology, Pathology and Laboratory Medicine, Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
4
|
Zhang X, Cui Y, He M, Jiao Y, Yang Z. Lipocalin-1 Expression as a Prognosticator Marker of Survival in Breast Cancer Patients. Breast Care (Basel) 2019; 15:272-280. [PMID: 32774222 DOI: 10.1159/000503168] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/04/2019] [Indexed: 12/26/2022] Open
Abstract
Purpose LCN1 (lipocalin-1), a gene that encodes tear lipocalin (or von Ebner's gland protein), is mainly expressed in secretory glands and tissues, such as the lachrymal and lingual gland, and nasal, mammary, and tracheobronchial mucosae. Analysis of the Cancer Genome Atlas (TCGA) Breast Carcinoma (BRCA) level 3 data revealed a relationship between LCN1 expression and survival in breast cancer patients. Methods The χ2 test and Fisher exact test were applied to analyze the clinical data and RNA sequencing expression data, and the association between LCN1 expression and clinicopathologic features was determined. The receiver-operating characteristic (ROC) curve of LCN1 was drawn to assess its ability as a diagnostic marker, and the optimal cutoff value was obtained from the ROC curve to distinguish groups with high and low LCN1 expression. Cox regression was used to compare both groups, and a log-rank test was applied to calculate p values and compare the -Kaplan-Meier curves. Furthermore, GEO datasets were employed for external data validation. Results Analysis of 1,104 breast cancer patients with a primary tumor revealed that LCN1 was overexpressed in breast cancer. High LCN1 expression was associated with clinicopathologic features and poor survival. Analyzing the area under the ROC curve (AUC) of LCN1, it was found that its diagnostic ability was limited. Multivariate analysis indicated that LCN1 expression is an independent predictor of survival in breast cancer patients. Through validation in GEO datasets, LCN1 expression was higher in tumor than normal tissue of the breast. High LCN1 expression was associated with poor survival in breast cancer patients. Conclusions High LCN1 expression is an independent prognosticator of a poor prognosis in breast cancer.
Collapse
Affiliation(s)
- Xueyan Zhang
- School of Nursing, Jilin University, Changchun, China
| | - Yingnan Cui
- Department of Breast Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Miao He
- Department of Anesthesia, The Second Hospital of Jilin University, Changchun, China
| | - Yan Jiao
- Department of Hepatobiliary and Pancreatic Surgery, The First Hospital of Jilin University, Changchun, China
| | - Zhaoying Yang
- Department of Breast Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
| |
Collapse
|
5
|
Yang Y, Li F, Luo X, Jia B, Zhao X, Liu B, Gao R, Yang L, Wei W, He J. Identification of LCN1 as a Potential Biomarker for Breast Cancer by Bioinformatic Analysis. DNA Cell Biol 2019; 38:1088-1099. [PMID: 31424267 DOI: 10.1089/dna.2019.4843] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The biological functions of lipocalin-1 (LCN1) are involved in innate immune responses and act as a physiological scavenger of potentially harmful lipophilic molecules. However, the relevance of LCN1 with cancer is rarely concerned currently. The aim of this study is to address the relevance of LCN1 with BRCA by bioinformatics. In this study, we found that the expressions of LCN1 increased significantly in various cancerous tissues, including BRCA, compared with their adjacent normal tissues through the TIMER database. Furthermore, UALCAN database analysis showed that the expression of LCN1 increased gradually from stage 1 to stage 4 and was upregulated in BRCA patients with different races and subtypes compared with that in the normal. In addition, those patients with perimenopause and postmenopause status displayed higher LCN1 expression. Importantly, LCN1 genetic alterations, including copy number amplification, deep deletion, and missense mutation, could be found, and the alteration frequency showed difference in various invasive BRCA through cBioPortal database. Moreover, a positive correlation between LCN1 somatic copy number alterations and immune cell enrichments was revealed in basal like BRCA by GISTIC 2.0. Finally, analysis on prognostic value of LCN1 by Kaplan-Meier plotter showed that low LCN1 expression correlated with poor prognosis for relapse-free survival in all types of BRCA, overall survival in luminal B BRCA, distant metastasis free survival in human epithelial growth factor receptor-2 (HER2) positive BRCA, and postprogression survival (PPS) in luminal A BRCA. But high LCN1 expression also displayed poor prognosis for PPS in HER2 positive BRCA. The results together verified the significance of LCN1 in BRCA, suggesting that it may be a potential biomarker for BRCA diagnosis.
Collapse
Affiliation(s)
- Yuemei Yang
- Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, Guangdong, P.R. China.,Department of R&D Technology Center, Beijing Zhicheng Biomedical Technology Co. Ltd., Beijing, P.R. China
| | - Feng Li
- Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, Guangdong, P.R. China
| | - Xueying Luo
- Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, Guangdong, P.R. China
| | - Binghan Jia
- Department of R&D Technology Center, Beijing Zhicheng Biomedical Technology Co. Ltd., Beijing, P.R. China
| | - Xiaoling Zhao
- Department of R&D Technology Center, Beijing Zhicheng Biomedical Technology Co. Ltd., Beijing, P.R. China
| | - Baoer Liu
- Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, Guangdong, P.R. China
| | - Rui Gao
- Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, Guangdong, P.R. China
| | - Liping Yang
- Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, Guangdong, P.R. China
| | - Wei Wei
- Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, Guangdong, P.R. China
| | - Jinsong He
- Department of Breast Surgery, Peking University Shenzhen Hospital, Shenzhen, Guangdong, P.R. China
| |
Collapse
|
6
|
Trenin AS, Arzumanian VG, Zhmak MN, Shelukhina IV, Makarova YV, Ivanov IA, Bychkova OP, Budikhina AS, Balyasova LS, Tsetlin VI. Synthesis and Antimicrobial Activity of a New Drug Based on a Retro-Analog of Cathelicidin—Polypeptide SE-33. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2019. [DOI: 10.1134/s1068162019020158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
7
|
Yenihayat F, Altıntaş Ö, Kasap M, Akpınar G, Güzel N, Çelik OS. Comparative proteome analysis of the tear samples in patients with low-grade keratoconus. Int Ophthalmol 2018; 38:1895-1905. [PMID: 28785876 DOI: 10.1007/s10792-017-0672-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 08/01/2017] [Indexed: 12/12/2022]
Abstract
PURPOSE To elucidate the metabolic processes playing roles in the formation of keratoconus (KC). METHODS Tears samples were collected using capillary glass tubes without stimulation and without prior anesthesia from 17 patients and 16 controls. Proteomic analysis by fluorescent 2D gel electrophoresis (DIGE) coupled with MALDI-TOF/TOF was performed. The identified proteins that were differentially regulated were subjected to Ingenuity Pathway Analysis (IPA). Corneal topography analyses with Sirius topography system (Costruzioni Strumenti Oftalmici, Florence, Italy) were performed on all participants. The steepest keratometry index was lower than 50 diopters in all keratoconus patients. RESULTS DIGE analysis showed changes in abundance of nine proteins. Six of these proteins, namely serum albumin, Keratin Type II Cytoskeletal 1, IgG gamma chain-1, GAPDH, alpha-1 antitrypsin and ApoA-I, were down-regulated in the KC samples in comparison with the controls. In addition, we detected up-regulation of lysozyme C, keratin type I cytoskeletal 10 and lipocalin. The subsequent IPA predicted that NADH repair pathway is activated in the KC patients. This pathway involves generation of NADHX as a by-product via catalysis by GAPDH. NADHX is an inhibitor of several dehydrogenases and must be removed. CONCLUSION The involvement of NADHX repair pathway in KC should be investigated, since preliminary clues obtained in this study point to that direction. In particular, showing the presence of ATP-dependent NAD(P)H-hydrate dehydratase that eliminates NADHX would strengthen our findings and would be a major step toward understanding KC.
Collapse
Affiliation(s)
- Fatih Yenihayat
- Department of Ophthalmology, Kocaeli State Hospital, 41100, Kocaeli, Turkey.
| | - Özgül Altıntaş
- Department of Ophthalmology, Medical School, Acıbadem University, Istanbul, Turkey
| | - Murat Kasap
- DEKART Proteomics Laboratory, Medical School, Kocaeli University, Kocaeli, Turkey
| | - Gürler Akpınar
- DEKART Proteomics Laboratory, Medical School, Kocaeli University, Kocaeli, Turkey
| | - Nil Güzel
- Department of Medical Biology, Medical School, Kocaeli University, Kocaeli, Turkey
| | - Onur Sinan Çelik
- Department of Ophthalmology, Tunceli State Hospital, Tunceli, Turkey
| |
Collapse
|
8
|
Lacritin and the tear proteome as natural replacement therapy for dry eye. Exp Eye Res 2013; 117:39-52. [PMID: 23769845 DOI: 10.1016/j.exer.2013.05.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 05/23/2013] [Accepted: 05/31/2013] [Indexed: 12/21/2022]
Abstract
Tear proteins are potential biomarkers, drug targets, and even biotherapeutics. As a biotherapeutic, a recombinant tear protein might physiologically rescue the ocular surface when a deficiency is detected. Such a strategy pays more attention to the natural prosecretory and protective properties of the tear film and seeks to alleviate symptoms by addressing cause, rather than the current palliative, non-specific and temporary approaches. Only a handful of tear proteins appear to be selectively downregulated in dry eye, the most common eye disease. Lacritin and lipocalin-1 are two tear proteins selectively deficient in dry eye. Both proteins influence ocular surface health. Lacritin is a prosecretory mitogen that promotes basal tearing when applied topically. Levels of active monomeric lacritin are negatively regulated by tear tissue transglutaminase, whose expression is elevated in dry eye with ocular surface inflammation. Lipocalin-1 is the master lipid sponge of the ocular surface, without which residual lipids could interfere with epithelial wetting. It also is a carrier for vitamins and steroid hormones, and is a key endonuclease. Accumulation of DNA in tears is thought to be proinflammatory. Functions of these and other tear proteins may be influenced by protein-protein interactions. Here we discuss new advances in lacritin biology and provide an overview on lipocalin-1, and newly identified members of the tear proteome.
Collapse
|
9
|
Proteomic analysis of human follicular fluid: a new perspective towards understanding folliculogenesis. J Proteomics 2013; 87:68-77. [PMID: 23707233 DOI: 10.1016/j.jprot.2013.05.017] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 04/23/2013] [Accepted: 05/14/2013] [Indexed: 01/20/2023]
Abstract
UNLABELLED Human follicular fluid is a complex body fluid that constitutes the microenvironment of developing follicles in the ovary. Follicular fluid contains a number of proteins that modulate oocyte maturation and ovulation. Information about the protein constituents of follicular fluid may provide a better understanding of ovarian physiology in addition to opening new avenues for investigating ovarian disorders. However, the composition of follicular fluid proteome remains poorly defined. In this study, we carried out SDS-PAGE, OFFGEL and SCX-based separation followed by LC-MS/MS analysis to characterize the proteome of human follicular fluid. We report high confidence identification of 480 proteins, of which 320 have not been described previously in the follicular fluid. The identified proteins belong to diverse functional categories including growth factor and hormones, receptor signaling, enzyme catalysis, defense/immunity and complement activity. Our dataset should serve as a resource for future studies aimed at developing biomarkers for monitoring oocyte and embryo quality, pregnancy outcomes and ovarian disorders. BIOLOGICAL SIGNIFICANCE Proteome analysis of human follicular fluid by multi-pronged approach of protein peptide fractionation revealed 480 proteins with high confidence. The identified protein may facilitate the understanding of folliculogenesis. This protein dataset should serve as a useful resource for development of biomarkers for oocyte quality, in vitro fertilization techniques and female infertility.
Collapse
|
10
|
Sia AK, Allred BE, Raymond KN. Siderocalins: Siderophore binding proteins evolved for primary pathogen host defense. Curr Opin Chem Biol 2012; 17:150-7. [PMID: 23265976 PMCID: PMC3634885 DOI: 10.1016/j.cbpa.2012.11.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 11/17/2012] [Accepted: 11/20/2012] [Indexed: 02/08/2023]
Abstract
Bacterial pathogens use siderophores to obtain iron from the host in order to survive and grow. The host defends against siderophore-mediated iron acquisition by producing siderocalins. Siderocalins are a siderophore binding subset of the lipocalin family of proteins. The design of the siderophore binding pocket gives siderocalins the ability to bind a wide variety of siderophores and protect the host against several pathogens. Siderocalins have been identified in humans, chickens, and quail, among other animals. The differences in the respective siderocalins suggest that each was developed in response to the most serious pathogens encountered by that animal. Additionally, siderocalins have been observed in many roles unrelated to pathogen defense including differentiation, embryogenesis, inflammation, and cancer.
Collapse
Affiliation(s)
- Allyson K Sia
- Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA
| | | | | |
Collapse
|
11
|
Abstract
Lipocalins are a family of diverse low molecular weight proteins that act extracellularly. They use multiple recognition properties that include 1) ligand binding to small hydrophobic molecules, 2) macromolecular complexation with other soluble macromolecules, and 3) binding to specific cell surface receptors to deliver cargo. Tear lipocalin (TLC) is a major protein in tears and has a large ligand-binding cavity that allows the lipocalin to bind an extensive and diverse set of lipophilic molecules. TLC can also bind to macromolecules, including the tear proteins lactoferin and lysozyme. The receptor to which TLC binds is termed tear lipocalin-interacting membrane receptor (LIMR). LIMR appears to work by endocytosis. TLC has a variety of suggested functions in tears, including regulation of tear viscosity, binding and release of lipids, endonuclease inactivation of viral DNA, binding of microbial siderophores (iron chelators used to deliver essential iron to bacteria), serving as a biomarker for dry eye, and possessing anti-inflammatory activity. Additional research is warranted to determine the actual functions of TLC in tears and the presence of its receptor on the ocular surface.
Collapse
Affiliation(s)
- Darlene A Dartt
- Schepens Eye Research Institute and Harvard Medical School, Boston, MA 02114, USA.
| |
Collapse
|
12
|
Gasymov OK, Abduragimov AR, Glasgow BJ. The conserved disulfide bond of human tear lipocalin modulates conformation and lipid binding in a ligand selective manner. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:671-83. [PMID: 21466861 DOI: 10.1016/j.bbapap.2011.03.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/28/2011] [Accepted: 03/29/2011] [Indexed: 11/26/2022]
Abstract
The primary aim of this study is the elucidation of the mechanism of disulfide induced alteration of ligand binding in human tear lipocalin (TL). Disulfide bonds may act as dynamic scaffolds to regulate conformational changes that alter protein function including receptor-ligand interactions. A single disulfide bond, (Cys61-Cys153), exists in TL that is highly conserved in the lipocalin superfamily. Circular dichroism and fluorescence spectroscopies were applied to investigate the mechanism by which disulfide bond removal effects protein stability, dynamics and ligand binding properties. Although the secondary structure is not altered by disulfide elimination, TL shows decreased stability against urea denaturation. Free energy change (ΔG(0)) decreases from 4.9±0.2 to 2.1±0.3kcal/mol with removal of the disulfide bond. Furthermore, ligand binding properties of TL without the disulfide vary according to the type of ligand. The binding of a bulky ligand, NBD-cholesterol, has a decreased time constant (from 11.8±0.2 to 3.3s). In contrast, the NBD-labeled phospholipid shows a moderate decrease in the time constant for binding, from 33.2±0.2 to 22.2±0.4s. FRET experiments indicate that the hairpin CD is directly involved in modulation of both ligand binding and flexibility of TL. In TL complexed with palmitic acid (PA-TL), the distance between the residues 62 of strand D and 81 of loop EF is decreased by disulfide bond reduction. Consequently, removal of the disulfide bond boosts flexibility of the protein to reach a CD-EF loop distance (24.3Å, between residues 62 and 81), which is not accessible for the protein with an intact disulfide bond (26.2Å). The results suggest that enhanced flexibility of the protein promotes a faster accommodation of the ligand inside the cavity and an energetically favorable ligand-protein complex.
Collapse
Affiliation(s)
- Oktay K Gasymov
- Department of Pathology, University of California, Los Angeles, USA.
| | | | | |
Collapse
|
13
|
Jessie K, Pang WW, Haji Z, Rahim A, Hashim OH. Proteomic analysis of whole human saliva detects enhanced expression of interleukin-1 receptor antagonist, thioredoxin and lipocalin-1 in cigarette smokers compared to non-smokers. Int J Mol Sci 2010; 11:4488-505. [PMID: 21151451 PMCID: PMC3000095 DOI: 10.3390/ijms11114488] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 10/25/2010] [Accepted: 11/05/2010] [Indexed: 01/30/2023] Open
Abstract
A gel-based proteomics approach was used to screen for proteins of differential abundance between the saliva of smokers and those who had never smoked. Subjecting precipitated proteins from whole human saliva of healthy non-smokers to two-dimensional electrophoresis (2-DE) generated typical profiles comprising more than 50 proteins. While 35 of the proteins were previously established by other researchers, an additional 22 proteins were detected in the 2-DE saliva protein profiles generated in the present study. When the 2-DE profiles were compared to those obtained from subjects considered to be heavy cigarette smokers, three saliva proteins, including interleukin-1 receptor antagonist, thioredoxin and lipocalin-1, showed significant enhanced expression. The distribution patterns of lipocalin-1 isoforms were also different between cigarette smokers and non-smokers. The three saliva proteins have good potential to be used as biomarkers for the adverse effects of smoking and the risk for inflammatory and chronic diseases that are associated with it.
Collapse
Affiliation(s)
- Kala Jessie
- Department of Oral Biology, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia; E-Mails: (K.J.); (Z.H.A.R.)
| | - Wei Wei Pang
- University of Malaya Centre for Proteomics Research, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia; E-Mail:
| | | | - Abdul Rahim
- Department of Oral Biology, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia; E-Mails: (K.J.); (Z.H.A.R.)
| | - Onn Haji Hashim
- University of Malaya Centre for Proteomics Research, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia; E-Mail:
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| |
Collapse
|
14
|
Kåredal MH, Mortstedt H, Jeppsson MC, Kronholm Diab K, Nielsen J, Jonsson BAG, Lindh CH. Time-dependent proteomic iTRAQ analysis of nasal lavage of hairdressers challenged by persulfate. J Proteome Res 2010; 9:5620-8. [PMID: 20815409 DOI: 10.1021/pr100436a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hairdressers are frequently exposed to bleaching powder containing persulfates, a group of compounds that may induce hypersensitivity in the airways. The mechanism causing this reaction is not clear. The aim of this study was to identify changes in the nasal lavage fluid proteome after challenge with potassium persulfate in hairdressers with bleaching powder-associated rhinitis. Furthermore, we aimed to compare their response to that of hairdressers without nasal symptoms, and atopic subjects with pollen-associated nasal symptoms. To study the pathogenesis of persulfate-associated rhinitis, the response in protein expression from the upper airway was assessed by time-dependent proteomic expression analysis of nasal lavage fluids. Samples were prepared by pooling nasal lavage fluids from the groups at different time points after challenge. Samples were depleted of high-abundant proteins, labeled with iTRAQ and analyzed by online 2D-nanoLC-MS/MS. Differences in the protein pattern between the three groups were observed. Most proteins with differentially expressed levels were involved in pathways of lipid transportation and antimicrobial activities. The major finding was increased abundance of apolipoprotein A-1, 20 min postchallenge, detected solely in the group of symptomatic hairdressers. Our results suggest there may be differences between the mechanisms responsible for the rhinitis in the symptomatic and atopic group.
Collapse
Affiliation(s)
- Monica H Kåredal
- Department of Laboratory Medicine, Lund University, SE-221 85 Lund, Sweden
| | | | | | | | | | | | | |
Collapse
|
15
|
Gasymov OK, Abduragimov AR, Glasgow BJ. Intracavitary ligand distribution in tear lipocalin by site-directed tryptophan fluorescence. Biochemistry 2009; 48:7219-28. [PMID: 19586017 DOI: 10.1021/bi9005557] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Site-directed tryptophan fluorescence has been successfully used to determine the solution structure of tear lipocalin. Here, the technique is extended to measure the binding energy landscape. Single Trp mutants of tear lipocalin are bound to the native ligand and an analogue tagged with a quencher group to both populate and discriminate the excited protein states. Steady-state and time-resolved fluorescence quenching data reveal the intracavitary state of the ligand. The static components of fluorescence quenching identify the residues where nonfluorescence complexes form. An asymmetric distribution of the ligand within the cavity reflects the complex energy landscape of the excited protein states. These findings suggest that the excited protein states are not unique but consist of many substates. The roughness of the binding energy landscape is about 2.5kBT. The excited protein states originate primarily from conformational selections of loops AB and GH, a portal region. In contrast to static quenching, the dynamic components of fluorescence quenching by the ligand are relevant to both local side chain and ligand dynamics. Apparent bimolecular rate constants for collisional quenching of Trp by the nitroxide moiety are approximately 1 / 5 x 10(12) M(-1) s(-1). Estimations made for effective ligand concentrations establish actual rate constants on the order of 12 x 10(9) M(-1) s(-1). Prior to exit from the cavity of the protein, ligands explore binding sites in nanoseconds. Although microsecond fluctuations are rate-limiting processes in ligand binding for many proteins, accompanying nanosecond motion may be necessary for propagation of ligand binding.
Collapse
Affiliation(s)
- Oktay K Gasymov
- Department of Pathology, UCLA School of Medicine, Jules Stein Eye Institute, 100 Stein Plaza, Los Angeles, California 90095, USA
| | | | | |
Collapse
|
16
|
Gasymov OK, Abduragimov AR, Glasgow BJ. Ligand binding site of tear lipocalin: contribution of a trigonal cluster of charged residues probed by 8-anilino-1-naphthalenesulfonic acid. Biochemistry 2008; 47:1414-24. [PMID: 18179255 DOI: 10.1021/bi701955e] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human tear lipocalin (TL) exhibits diverse functions, most of which are linked to ligand binding. To map the binding site of TL for some amphiphilic ligands, we capitalized on the hydrophobic and hydrophilic properties of 8-anilino-1-naphthalenesulfonic acid (ANS). In single Trp mutants, resonance energy transfer from Trp to ANS indicates that the naphthalene group of ANS is proximate to Leu105 in the cavity. Binding energies of TL to ANS and its analogues reveal contributions from electrostatic interactions. The sulfonate group of ANS interacts strongly with the nonconserved intracavitary residue Lys114 and less with neighboring residues His84 and Glu34. This trigonal cluster of residues may play a role in the ligand recognition site for some negatively charged ligands. Because many drugs possess sulfonate groups, the trigonal cluster-sulfonate interaction can also be exploited as a lipocalin-based drug delivery mechanism. The binding of lauric acid and its analogues shows that fatty acids assume heterogeneous orientations in the cavity of TL. Predominantly, the hydrocarbon tail is buried in the cavity of TL and the carboxyl group is oriented toward the mouth. However, TL can also interact, albeit relatively weakly, with fatty acids oriented in the opposite direction. As the major lipid binding protein of tears, the ability to accommodate fatty acids in two opposing orientations may have functional implications for TL. At the aqueous-lipid interface, fatty acids whose carboxyl groups are positioned toward the aqueous phase are available for interaction with TL that could augment stability of the tear film.
Collapse
Affiliation(s)
- Oktay K Gasymov
- Department of Pathology, Jules Stein Eye Institute, UCLA School of Medicine, 100 Stein Plaza, Los Angeles, California 90095, USA
| | | | | |
Collapse
|
17
|
Grzyb J, Latowski D, Strzałka K. Lipocalins - a family portrait. JOURNAL OF PLANT PHYSIOLOGY 2006; 163:895-915. [PMID: 16504339 DOI: 10.1016/j.jplph.2005.12.007] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Accepted: 12/12/2005] [Indexed: 05/06/2023]
Abstract
Lipocalins are a widely distributed group of proteins whose common feature is the presence of six-or eight-stranded beta-barrel in their tertiary structure and highly conservative motifs short conserved region, (SCR) in their amino acid sequences. The presence of three SCRs is typical for kernel lipocalins, while outlier lipocalins have only one or two such regions. Owing to their ability to bind and transport small, hydrophobic molecules, lipocalins participate in the distribution of such substances. However, the physiological significance of lipocalins is not limited to transfer processes. They play an important role in the regulation of immunological and developmental processes, and are also involved in the reactions of organisms to various stress factors and in the pathways of signal transduction. Of special interest is the enzymatic activity found in a few members of the lipocalin family, as well as the interaction with natural membranes, both directly with lipids and through membrane-localized protein receptors.
Collapse
Affiliation(s)
- Joanna Grzyb
- Department of Plant Physiology and Biochemistry, Faculty of Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków, Poland
| | | | | |
Collapse
|
18
|
Tsai PS, Evans JE, Green KM, Sullivan RM, Schaumberg DA, Richards SM, Dana MR, Sullivan DA. Proteomic analysis of human meibomian gland secretions. Br J Ophthalmol 2006; 90:372-7. [PMID: 16488965 PMCID: PMC1856970 DOI: 10.1136/bjo.2005.080846] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND/AIM Human tears contain hundreds of proteins that may exert a significant influence on tear film stability, ocular surface integrity, and visual function. The authors hypothesise that many of these proteins originate from the meibomian gland. This study's aim was to begin to develop the proteomic methodology to permit the testing of their hypothesis. METHODS Meibomian gland secretions were collected from the lower eyelids of adult volunteers and placed in a chloroform-methanol mixture. Samples were partitioned in a biphasic system and non-lipid phase materials were reduced, alkylated, and trypsin digested to obtain peptides for protein identification. This peptide mixture was separated by micro-capillary reverse phase chromatography and the effluent examined by nano-electrospray MS and data dependent MS/MS. SEQUEST software was used to identify proteins from the MS/MS spectra. RESULTS The methodological approach to date has permitted the identification of more than 90 proteins in human meibomian gland secretions. Proteins include the alpha2-macroglobulin receptor, IgA alpha chain, farnesoid X activated receptor, interferon regulatory factor 3, lacritin precursor, lactotransferrin, lipocalin 1, lysozyme C precursor, potential phospholipid transporting ATPase IK, seven transmembrane helix receptor (also termed somatostatin receptor type 4), testes development related NYD-SP21 (also termed high affinity IgE receptor beta subunit), and TrkC tyrosine kinase. CONCLUSIONS These findings indicate that the meibomian gland secretes a number of proteins into the tear film. It is quite possible that these proteins contribute to the dynamics of the tear film in both health and disease.
Collapse
Affiliation(s)
- P S Tsai
- Schepens Eye Research Institute, 20 Staniford Street, Boston, MA 02114, USA
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Gouveia SM, Tiffany JM. Human tear viscosity: An interactive role for proteins and lipids. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1753:155-63. [PMID: 16236563 DOI: 10.1016/j.bbapap.2005.08.023] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2003] [Revised: 08/26/2005] [Accepted: 08/30/2005] [Indexed: 11/20/2022]
Abstract
Human tear viscosity is poorly understood. Tears need to remain on the ocular surface for lubrication without causing damage to the surface epithelia due to drag when blinking. Whole tears are shear-thinning (non-Newtonian), which cannot be explained by the amount of mucin present, nor by individual proteins. Whole tears minus lipids become Newtonian. Though no free lipids had previously been found in collected tears, tear lipocalin (TL), a major tear protein, is known to bind lipids. In this study, we aimed to confirm whether there are any free lipids in collected tears, and to clarify the combined contribution of tear proteins to viscosity, including experiments on recombinant TL, both without (apo-TL) and with (holo-TL) bound lipid. We also investigated possible oligomer formation by holo- and apo-TL as a mechanism for viscosity using SDS-PAGE and analytical ultracentrifugation (AU). For comparison, we have included results for beta-lactoglobulin, a well-characterised lipocalin protein. No free lipids were detected in whole tears. Rheology showed that any protein combination that included lysozyme or lactoferrin was shear-thinning, as was apo-TL, though holo-TL was Newtonian (linear). Results from SDS-PAGE and AU showed apo-TL to be entirely monomeric, but holo-TL showed some dimerization. Both apo- and holo-beta-lactoglobulin exhibited a monomer-dimer equilibrium. We conclude that hetero-protein interactions, possibly electrostatic, involving lipid-binding-induced structural changes to TL, significantly contribute to the viscosity of human tears.
Collapse
Affiliation(s)
- Scott M Gouveia
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, OX2 6AW, UK
| | | |
Collapse
|
20
|
Breustedt DA, Korndörfer IP, Redl B, Skerra A. The 1.8-Å Crystal Structure of Human Tear Lipocalin Reveals an Extended Branched Cavity with Capacity for Multiple Ligands. J Biol Chem 2005; 280:484-93. [PMID: 15489503 DOI: 10.1074/jbc.m410466200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In contrast with earlier assumptions, which classified human tear lipocalin (Tlc) as an outlier member of the lipocalin protein family, the 1.8-A resolution crystal structure of the recombinant apoprotein confirms the typical eight-stranded antiparallel beta-barrel architecture with an alpha-helix attached to it. The fold of Tlc most closely resembles the bovine dander allergen Bos d 2, a well characterized prototypic lipocalin, but also reveals similarity with beta-lactoglobulin. However, compared with other lipocalin structures Tlc exhibits an extremely wide ligand pocket, whose entrance is formed by four partially disordered loops. The cavity deeply extends into the beta-barrel structure, where it ends in two distinct lobes. This unusual structural feature explains the known promiscuity of Tlc for various ligands, with chemical structures ranging from lipids and retinoids to the macrocyclic antibiotic rifampin and even to microbial siderophores. Notably, earlier findings of biological activity as a thiol protease inhibitor have no correspondence in the three-dimensional structure of Tlc, rather it appears that its proteolytic fragments could be responsible for this phenomenon. Hence, the present structural analysis sheds new light on the ligand binding activity of this functionally obscure but abundant human lipocalin.
Collapse
Affiliation(s)
- Daniel A Breustedt
- Lehrstuhl für Biologische Chemie, Technische Universität München, D-85350 Freising-Weihenstephan, Germany
| | | | | | | |
Collapse
|
21
|
Gasymov OK, Abduragimov AR, Gasimov EO, Yusifov TN, Dooley AN, Glasgow BJ. Tear lipocalin: potential for selective delivery of rifampin. Biochim Biophys Acta Mol Basis Dis 2004; 1688:102-11. [PMID: 14990340 DOI: 10.1016/j.bbadis.2003.11.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2003] [Revised: 09/29/2003] [Accepted: 11/07/2003] [Indexed: 11/20/2022]
Abstract
The potential of ligand binding proteins as drug carriers and delivery systems has recently sparked great interest. We investigated the potential of tear lipocalin (TL) to bind the antibiotic, rifampin, and the environmental conditions for controlled release. To determine if TL binds rifampin, gel filtration was used to isolate protein fractions of tears. Rifampin was detected by absorbance spectroscopy in the elution fractions containing TL. The bound complex of rifampin-TL generates optical activity at about 360 nm, indicating a unique conformation at the binding site. Rifampin has a higher affinity for TL (Kd=128 microM) than albumin. Rifampin is released from the TL calyx in acidic conditions and is displaced by palmitic acid. Autooxidation of free rifampin begins in minutes but is delayed by at least 3 h in the presence of TL. These properties are conducive to stabilization and delivery of rifampin to tubercles that are acidic and rich in fatty acids. These studies show the potential of TL as a carrier for rifampin with controlled release to a targeted environment.
Collapse
Affiliation(s)
- Oktay K Gasymov
- Department of Pathology, Jules Stein Eye Institute, University of California, 100 Stein Plaza Rm B-279, Los Angeles, CA 90095, USA
| | | | | | | | | | | |
Collapse
|