101
|
Yamamoto H, Ramos-Molina B, Lick AN, Prideaux M, Albornoz V, Bonewald L, Lindberg I. Posttranslational processing of FGF23 in osteocytes during the osteoblast to osteocyte transition. Bone 2016; 84:120-130. [PMID: 26746780 PMCID: PMC4755901 DOI: 10.1016/j.bone.2015.12.055] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/04/2015] [Accepted: 12/09/2015] [Indexed: 11/29/2022]
Abstract
FGF23 is an O-glycosylated circulating peptide hormone with a critical role in phosphate homeostasis; it is inactivated by cellular proprotein convertases in a pre-release degradative pathway. We have here examined the metabolism of FGF23 in a model bone cell line, IDG-SW3, prior to and following differentiation, as well as in regulated secretory cells. Labeling experiments showed that the majority of (35)S-labeled FGF23 was cleaved to smaller fragments which were constitutively secreted by all cell types. Intact FGF23 was much more efficiently stored in differentiated than in undifferentiated IDG-SW3 cells. The prohormone convertase PC2 has recently been implicated in FGF23 degradation; however, FGF23 was not targeted to forskolin-stimulatable secretory vesicles in a regulated cell line, suggesting that it lacks a targeting signal to PC2-containing compartments. In vitro, PC1/3 and PC2, but not furin, efficiently cleaved glycosylated FGF23; surprisingly, PC5/6 accomplished a small amount of conversion. FGF23 has recently been shown to be phosphorylated by the kinase FAM20C, a process which was shown to reduce FGF23 glycosylation and promote its cleavage; our in vitro data, however, show that phosphorylation does not directly impact cleavage, as both PC5/6 and furin were able to efficiently cleave unglycosylated, phosphorylated FGF23. Using qPCR, we found that the expression of FGF23 and PC5/6, but not PC2 or furin, increased substantially following osteoblast to osteocyte differentiation. Western blotting confirmed the large increase in PC5/6 expression upon differentiation. FGF23 has been linked to a variety of bone disorders ranging from autosomal dominant hypophosphatemic rickets to chronic kidney disease. A better understanding of the biosynthetic pathway of this hormone may lead to new treatments for these diseases.
Collapse
Affiliation(s)
- Hiroyuki Yamamoto
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Bruno Ramos-Molina
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Adam N Lick
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Matthew Prideaux
- School of Dentistry, Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Valeria Albornoz
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Lynda Bonewald
- School of Dentistry, Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| |
Collapse
|
102
|
Sivanesan D, Beauchamp C, Quinou C, Lee J, Lesage S, Chemtob S, Rioux JD, Michnick SW. IL23R (Interleukin 23 Receptor) Variants Protective against Inflammatory Bowel Diseases (IBD) Display Loss of Function due to Impaired Protein Stability and Intracellular Trafficking. J Biol Chem 2016; 291:8673-85. [PMID: 26887945 DOI: 10.1074/jbc.m116.715870] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Indexed: 01/19/2023] Open
Abstract
Genome-wide association studies as well as murine models have shown that the interleukin 23 receptor (IL23R) pathway plays a pivotal role in chronic inflammatory diseases such as Crohn disease (CD), ulcerative colitis, psoriasis, and type 1 diabetes. Genome-wide association studies and targeted re-sequencing studies have revealed the presence of multiple potentially causal variants of the IL23R. Specifically the G149R, V362I, and R381Q IL23Rα chain variants are linked to protection against the development of Crohn disease and ulcerative colitis in humans. Moreover, the exact mechanism of action of these receptor variants has not been elucidated. We show that all three of these IL23Rα variants cause a reduction in IL23 receptor activation-mediated phosphorylation of the signal-transducing activator of transcription 3 (STAT3) and phosphorylation of signal transducing activator of transcription 4 (STAT4). The reduction in signaling is due to lower levels of cell surface receptor expression. For G149R, the receptor retention in the endoplasmic reticulum is due to an impairment of receptor maturation, whereas the R381Q and V362I variants have reduced protein stability. Finally, we demonstrate that the endogenous expression of IL23Rα protein from V362I and R381Q variants in human lymphoblastoid cell lines exhibited lower expression levels relative to susceptibility alleles. Our results suggest a convergent cause of IL23Rα variant protection against chronic inflammatory disease.
Collapse
Affiliation(s)
- Durga Sivanesan
- From the Department of Biochemistry, University of Montreal, Montreal, Quebec H3C 3J7, Canada, University of Ottawa, Department of Biochemistry, Microbiology, and Immunology, Ottawa, Ontario K1H 8M5, Canada
| | - Claudine Beauchamp
- University of Montreal and the Montreal Heart Institute, Research Center, Montreal, Quebec H1T 1C8, Canada
| | - Christiane Quinou
- CHU Sainte-Justine, Research Centre, Montreal, Quebec H3T 1C5, Canada, and
| | - Jonathan Lee
- University of Ottawa, Department of Biochemistry, Microbiology, and Immunology, Ottawa, Ontario K1H 8M5, Canada
| | - Sylvie Lesage
- Centre of Recherche Hospital Maisonneuve-Rosemont, Department of Microbiology, Infection, and Immunology, University of Montreal, Montreal, Quebec H1T 2M4, Canada
| | - Sylvain Chemtob
- CHU Sainte-Justine, Research Centre, Montreal, Quebec H3T 1C5, Canada, and
| | - John D Rioux
- University of Montreal and the Montreal Heart Institute, Research Center, Montreal, Quebec H1T 1C8, Canada
| | - Stephen W Michnick
- From the Department of Biochemistry, University of Montreal, Montreal, Quebec H3C 3J7, Canada,
| |
Collapse
|
103
|
Update on the molecular biology of dyslipidemias. Clin Chim Acta 2016; 454:143-85. [DOI: 10.1016/j.cca.2015.10.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/24/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
|
104
|
Stijnen P, Brouwers B, Dirkx E, Ramos-Molina B, Van Lommel L, Schuit F, Thorrez L, Declercq J, Creemers JWM. Endoplasmic reticulum-associated degradation of the mouse PC1/3-N222D hypomorph and human PCSK1 mutations contributes to obesity. Int J Obes (Lond) 2016; 40:973-81. [PMID: 26786350 DOI: 10.1038/ijo.2016.3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 12/03/2015] [Accepted: 12/22/2015] [Indexed: 12/26/2022]
Abstract
BACKGROUND The proprotein convertase 1/3 (PC1/3), encoded by proprotein convertase subtilisin/kexin type 1 (PCSK1), cleaves and hence activates several orexigenic and anorexigenic proproteins. Congenital inactivation of PCSK1 leads to obesity in human but not in mice. However, a mouse model harboring the hypomorphic mutation N222D is obese. It is not clear why the mouse models differ in phenotype. METHODS Gene expression analysis was performed with pancreatic islets from Pcsk1(N222D/N222D) mice. Subsequently, biosynthesis, maturation, degradation and activity were studied in islets, pituitary, hypothalamus and cell lines. Coimmunoprecipitation of PC1/3-N222D and human PC1/3 variants associated with obesity with the endoplasmic reticulum (ER) chaperone BiP was studied in cell lines. RESULTS Gene expression analysis of islets of Pcsk1(N222D/N222D) mice showed enrichment of gene sets related to the proteasome and the unfolded protein response. Steady-state levels of PC1/3-N222D and in particular the carboxy-terminally processed form were strongly reduced in islets, pituitary and hypothalamus. However, impairment of substrate cleavage was tissue dependent. Proinsulin processing was drastically reduced, while processing of proopiomelanocortin (POMC) to adrenocorticotropic hormone (ACTH) in pituitary was only mildly impaired. Growth hormone expression and IGF-1 levels were normal, indicating near-normal processing of hypothalamic proGHRH. PC1/3-N222D binds to BiP and is rapidly degraded by the proteasome. Analysis of human PC1/3 obesity-associated mutations showed increased binding to BiP and prolonged intracellular retention for all investigated mutations, in particular for PC1/3-T175M, PC1/3-G226R and PC1/3-G593R. CONCLUSIONS This study demonstrates that the hypomorphic mutation in Pcsk1(N222D) mice has an effect on catalytic activity in pancreatic islets, pituitary and hypothalamus. Reduced substrate processing activity in Pcsk1(N222D/N222D) mice is due to enhanced degradation in addition to reduced catalytic activity of the mutant. PC1/3-N222D binds to BiP, suggesting impaired folding and reduced stability. Enhanced BiP binding is also observed in several human obesity-associated PC1/3 variants, suggesting a common mechanism.
Collapse
Affiliation(s)
- P Stijnen
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - B Brouwers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - E Dirkx
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - B Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - L Van Lommel
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - F Schuit
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - L Thorrez
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - J Declercq
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - J W M Creemers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven, Belgium
| |
Collapse
|
105
|
Gorski JP, Huffman NT, Vallejo J, Brotto L, Chittur SV, Breggia A, Stern A, Huang J, Mo C, Seidah NG, Bonewald L, Brotto M. Deletion of Mbtps1 (Pcsk8, S1p, Ski-1) Gene in Osteocytes Stimulates Soleus Muscle Regeneration and Increased Size and Contractile Force with Age. J Biol Chem 2015; 291:4308-22. [PMID: 26719336 DOI: 10.1074/jbc.m115.686626] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 12/28/2022] Open
Abstract
Conditional deletion of Mbtps1 (cKO) protease in bone osteocytes leads to an age-related increase in mass (12%) and in contractile force (30%) in adult slow twitch soleus muscles (SOL) with no effect on fast twitch extensor digitorum longus muscles. Surprisingly, bone from 10-12-month-old cKO animals was indistinguishable from controls in size, density, and morphology except for a 25% increase in stiffness. cKO SOL exhibited increased expression of Pax7, Myog, Myod1, Notch, and Myh3 and 6-fold more centralized nuclei, characteristics of postnatal regenerating muscle, but only in type I myosin heavy chain-expressing cells. Increased expression of gene pathways mediating EGF receptor signaling, circadian exercise, striated muscle contraction, and lipid and carbohydrate oxidative metabolism were also observed in cKO SOL. This muscle phenotype was not observed in 3-month-old mice. Although Mbtps1 mRNA and protein expression was reduced in cKO bone osteocytes, no differences in Mbtps1 or cre recombinase expression were observed in cKO SOL, explaining this age-related phenotype. Understanding bone-muscle cross-talk may provide a fresh and novel approach to prevention and treatment of age-related muscle loss.
Collapse
Affiliation(s)
- Jeff P Gorski
- From the Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City Center of Excellence in the Study of Dental and Musculoskeletal Tissues, School of Dentistry,
| | - Nichole T Huffman
- From the Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City Center of Excellence in the Study of Dental and Musculoskeletal Tissues, School of Dentistry
| | - Julian Vallejo
- Muscle Biology Research Group, School of Nursing and Health Studies, and
| | - Leticia Brotto
- Muscle Biology Research Group, School of Nursing and Health Studies, and
| | - Sridar V Chittur
- Center for Functional Genomics, University at Albany, Rensselaer, New York 12144
| | | | - Amber Stern
- School of Computing and Engineering, University of Missouri-Kansas City, Kansas City, Missouri 64108, Engineering Systems, Inc., Charlotte, North Carolina 28277, and
| | - Jian Huang
- Muscle Biology Research Group, School of Nursing and Health Studies, and
| | - Chenglin Mo
- Muscle Biology Research Group, School of Nursing and Health Studies, and
| | - Nabil G Seidah
- Institut de Recherches Cliniques Montreal, Montreal, Quebec H2W IR7, Canada
| | - Lynda Bonewald
- From the Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City Center of Excellence in the Study of Dental and Musculoskeletal Tissues, School of Dentistry
| | - Marco Brotto
- Muscle Biology Research Group, School of Nursing and Health Studies, and
| |
Collapse
|
106
|
Hook V, Bandeira N. Neuropeptidomics Mass Spectrometry Reveals Signaling Networks Generated by Distinct Protease Pathways in Human Systems. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1970-80. [PMID: 26483184 PMCID: PMC4749436 DOI: 10.1007/s13361-015-1251-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 07/30/2015] [Accepted: 08/05/2015] [Indexed: 05/23/2023]
Abstract
Neuropeptides regulate intercellular signaling as neurotransmitters of the central and peripheral nervous systems, and as peptide hormones in the endocrine system. Diverse neuropeptides of distinct primary sequences of various lengths, often with post-translational modifications, coordinate and integrate regulation of physiological functions. Mass spectrometry-based analysis of the diverse neuropeptide structures in neuropeptidomics research is necessary to define the full complement of neuropeptide signaling molecules. Human neuropeptidomics has notable importance in defining normal and dysfunctional neuropeptide signaling in human health and disease. Neuropeptidomics has great potential for expansion in translational research opportunities for defining neuropeptide mechanisms of human diseases, providing novel neuropeptide drug targets for drug discovery, and monitoring neuropeptides as biomarkers of drug responses. In consideration of the high impact of human neuropeptidomics for health, an observed gap in this discipline is the few published articles in human neuropeptidomics compared with, for example, human proteomics and related mass spectrometry disciplines. Focus on human neuropeptidomics will advance new knowledge of the complex neuropeptide signaling networks participating in the fine control of neuroendocrine systems. This commentary review article discusses several human neuropeptidomics accomplishments that illustrate the rapidly expanding diversity of neuropeptides generated by protease processing of pro-neuropeptide precursors occurring within the secretory vesicle proteome. Of particular interest is the finding that human-specific cathepsin V participates in producing enkephalin and likely other neuropeptides, indicating unique proteolytic mechanisms for generating human neuropeptides. The field of human neuropeptidomics has great promise to solve new mechanisms in disease conditions, leading to new drug targets and therapeutic agents for human diseases. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093-0719, USA.
- School of Medicine, Department of Neurosciences and Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093-0719, USA.
| | - Nuno Bandeira
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093-0719, USA
- Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA, 92093-0719, USA
| |
Collapse
|
107
|
Seidah NG. The PCSK9 revolution and the potential of PCSK9-based therapies to reduce LDL-cholesterol. Glob Cardiol Sci Pract 2015. [DOI: 10.5339/gcsp.2015.59] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
108
|
Lee SN, Lee DH, Lee MG, Yoon JH. Proprotein convertase 5/6a is associated with bone morphogenetic protein-2-induced squamous cell differentiation. Am J Respir Cell Mol Biol 2015; 52:749-61. [PMID: 25350918 DOI: 10.1165/rcmb.2014-0029oc] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Squamous metaplasia in airway epithelium is a pathological process arising from abnormal remodeling/repair responses to injury. Proteolytic maturation of many growth and differentiation factors involved in tissue remodeling is controlled by proprotein convertases (PCs). However, the role of these convertases in airway remodeling remains poorly understood. Using a retinoic acid deficiency-induced squamous metaplasia model of cultured human nasal epithelial cells (HNECs), we observed a significant increase in the expression of PC5/6A, a PC member, and bone morphogenetic protein-2 (BMP-2), a candidate substrate for PC5/6A. Specific lentiviral short hairpin RNA-mediated PC5/6A knockdown decreased BMP-2 expression and maturation, decreased expression of squamous cell markers, and increased expression of ciliated cell markers. Decanoyl-Arg-Val-Lys-Arg-chloromethylketone (Dec-RVKR-CMK), a PC inhibitor, and LDN-193189, a BMP receptor inhibitor, suppressed squamous differentiation, promoted mucociliary differentiation, and down-regulated the BMP-2/Smad1/5/8/p38 signaling pathways. Dec-RVKR-CMK also decreased expression of PC5/6A, but not furin, another PC member, suggesting the involvement of PC5/6A in squamous differentiation of HNECs. Overexpression of PC5/6A and BMP-2 in the human nasal epithelial cell line RPMI-2650 demonstrated that PC5/6A can activate BMP-2. Under retinoic acid-sufficient culture conditions for mucociliary differentiation of HNECs, short-term expression of PC5/6A by the adenovirus system and addition of exogenous BMP-2 induced squamous differentiation. Furthermore, PC5/6A and BMP-2 were highly expressed in metaplastic squamous epithelium of human nasal polyps. Taken together, PC5/6A is involved in squamous differentiation of HNECs, possibly through up-regulation of the BMP-2/pSmad1/5/8/p38 signaling pathway, pointing to a potential therapeutic target for the prevention of chronic airway diseases that exhibit squamous metaplasia.
Collapse
Affiliation(s)
- Sang-Nam Lee
- 1 Research Center for Human Natural Defense System
| | | | | | | |
Collapse
|
109
|
PCSK6-mediated corin activation is essential for normal blood pressure. Nat Med 2015; 21:1048-53. [PMID: 26259032 DOI: 10.1038/nm.3920] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 07/13/2015] [Indexed: 12/22/2022]
Abstract
Hypertension is the most common cardiovascular disease, afflicting >30% of adults. The cause of hypertension in most individuals remains unknown, suggesting that additional contributing factors have yet to be discovered. Corin is a serine protease that activates the natriuretic peptides, thereby regulating blood pressure. It is synthesized as a zymogen that is activated by proteolytic cleavage. CORIN variants and mutations impairing corin activation have been identified in people with hypertension and pre-eclampsia. To date, however, the identity of the protease that activates corin remains elusive. Here we show that proprotein convertase subtilisin/kexin-6 (PCSK6, also named PACE4; ref. 10) cleaves and activates corin. In cultured cells, we found that corin activation was inhibited by inhibitors of PCSK family proteases and by small interfering RNAs blocking PCSK6 expression. Conversely, PCSK6 overexpression enhanced corin activation. In addition, purified PCSK6 cleaved wild-type corin but not the R801A variant that lacks the conserved activation site. Pcsk6-knockout mice developed salt-sensitive hypertension, and corin activation and pro-atrial natriuretic peptide processing activity were undetectable in these mice. Moreover, we found that CORIN variants in individuals with hypertension and pre-eclampsia were defective in PCSK6-mediated activation. We also identified a PCSK6 mutation that impaired corin activation activity in a hypertensive patient. Our results indicate that PCSK6 is the long-sought corin activator and is important for sodium homeostasis and normal blood pressure.
Collapse
|
110
|
Abstract
PURPOSE OF REVIEW The proprotein convertases subtilisin/kexin (PCSKs) are endoproteases identified as activators of precursors from hormones and peptides. On the basis of the variety of substrates and regulation in disease, they have been recognized as mediators in atherogenesis. The discovery of PCSK9, which regulates low-density lipoprotein receptor cell membrane availability, has led to a resurgence of interest in these enzymes and their function in cardiovascular diseases. RECENT FINDINGS Recent data demonstrate that PCSKs are expressed in human atheroma and are regulated in animal models of atherosclerosis. In animal models, inhibition of PCSKs, such as PCSK3, affects cell proliferation and migration as well as inflammation, reducing atherosclerosis. In addition, targeting PCSK9 lowers cholesterol levels and has now been demonstrated to lessen vascular lesion formation in mice. Experimentally investigated novel anti-PCSK9 strategies include genome editing and vaccination. Furthermore, studies show that PCSKs contribute to the initiation and progression of cardiometabolic risk factors, such as insulin resistance and obesity. SUMMARY PCSKs affect cardiovascular diseases on multiple levels, including atherosclerotic lesion formation as well as their contribution to cardiometabolic risk factors. PCSK9 is a key regulator of plasma cholesterol levels, thereby potentially affecting atherosclerosis and has rapidly emerged as a pharmacological target.
Collapse
Affiliation(s)
- Philipp Stawowy
- Deutsches Herzzentrum Berlin, Department of Medicine/Cardiology, Berlin, Germany
| |
Collapse
|
111
|
Williamson DM, Elferich J, Shinde U. Mechanism of Fine-tuning pH Sensors in Proprotein Convertases: IDENTIFICATION OF A pH-SENSING HISTIDINE PAIR IN THE PROPEPTIDE OF PROPROTEIN CONVERTASE 1/3. J Biol Chem 2015; 290:23214-25. [PMID: 26229104 DOI: 10.1074/jbc.m115.665430] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Indexed: 12/15/2022] Open
Abstract
The propeptides of proprotein convertases (PCs) regulate activation of cognate protease domains by sensing pH of their organellar compartments as they transit the secretory pathway. Earlier experimental work identified a conserved histidine-encoded pH sensor within the propeptide of the canonical PC, furin. To date, whether protonation of this conserved histidine is solely responsible for PC activation has remained unclear because of the observation that various PC paralogues are activated at different organellar pH values. To ascertain additional determinants of PC activation, we analyzed PC1/3, a paralogue of furin that is activated at a pH of ∼5.4. Using biophysical, biochemical, and cell-based methods, we mimicked the protonation status of various histidines within the propeptide of PC1/3 and examined how such alterations can modulate pH-dependent protease activation. Our results indicate that whereas the conserved histidine plays a crucial role in pH sensing and activation of this protease an additional histidine acts as a "gatekeeper" that fine-tunes the sensitivity of the PC1/3 propeptide to facilitate the release inhibition at higher proton concentrations when compared with furin. Coupled with earlier analyses that highlighted the enrichment of the amino acid histidine within propeptides of secreted eukaryotic proteases, our work elucidates how secreted proteases have evolved to exploit the pH of the secretory pathway by altering the spatial juxtaposition of titratable groups to regulate their activity in a spatiotemporal fashion.
Collapse
Affiliation(s)
- Danielle M Williamson
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Johannes Elferich
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Ujwal Shinde
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| |
Collapse
|
112
|
Druce I, Abujrad H, Ooi TC. PCSK9 and triglyceride-rich lipoprotein metabolism. J Biomed Res 2015; 29. [PMID: 26320603 PMCID: PMC4662203 DOI: 10.7555/jbr.29.20150052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 07/01/2015] [Indexed: 12/26/2022] Open
Abstract
Pro-protein convertase subtilisin-kexin 9 (PCSK9) is known to affect low-density lipoprotein (LDL) metabolism, but there are indications from several lines of research that it may also influence the metabolism of other lipoproteins, especially triglyceride-rich lipoproteins (TRL). This review summarizes the current data on this possible role of PCSK9. A link between PCSK9 and TRL has been suggested through the demonstration of (1) a correlation between plasma PCSK9 and triglyceride (TG) levels in health and disease, (2) a correlation between plasma PCSK9 and markers of carbohydrate metabolism, which is closely related to TG metabolism, (3) an effect of TG-lowering fibrate therapy on plasma PCSK9 levels, (4) an effect of PCSK9 on postprandial lipemia, (5) an effect of PCSK9 on adipose tissue biology, (6) an effect of PCSK9 on apolipoprotein B production from the liver and intestines, (7) an effect of PCSK9 on receptors other than low density lipoprotein receptor (LDLR) that are involved in TRL metabolism, and (8) an effect of anti-PCSK9 therapy on serum TG levels. The underlying mechanisms are unclear but starting to emerge.
Collapse
Affiliation(s)
- I Druce
- Clinical Research Laboratory, Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Ontario K1H 8L6, Canada
| | - H Abujrad
- Clinical Research Laboratory, Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Ontario K1H 8L6, Canada
| | - T C Ooi
- Clinical Research Laboratory, Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Ontario K1H 8L6, Canada.,Chronic Disease Program, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario K1H 7W9, Canada.
| |
Collapse
|
113
|
Vaudry H, Leprince J, Chatenet D, Fournier A, Lambert DG, Le Mével JC, Ohlstein EH, Schwertani A, Tostivint H, Vaudry D. International Union of Basic and Clinical Pharmacology. XCII. Urotensin II, urotensin II-related peptide, and their receptor: from structure to function. Pharmacol Rev 2015; 67:214-58. [PMID: 25535277 DOI: 10.1124/pr.114.009480] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Urotensin II (UII) is a cyclic neuropeptide that was first isolated from the urophysis of teleost fish on the basis of its ability to contract the hindgut. Subsequently, UII was characterized in tetrapods including humans. Phylogenetic studies and synteny analysis indicate that UII and its paralogous peptide urotensin II-related peptide (URP) belong to the somatostatin/cortistatin superfamily. In mammals, the UII and URP genes are primarily expressed in cholinergic neurons of the brainstem and spinal cord. UII and URP mRNAs are also present in various organs notably in the cardiovascular, renal, and endocrine systems. UII and URP activate a common G protein-coupled receptor, called UT, that exhibits relatively high sequence identity with somatostatin, opioid, and galanin receptors. The UT gene is widely expressed in the central nervous system (CNS) and in peripheral tissues including the retina, heart, vascular bed, lung, kidney, adrenal medulla, and skeletal muscle. Structure-activity relationship studies and NMR conformational analysis have led to the rational design of a number of peptidic and nonpeptidic UT agonists and antagonists. Consistent with the wide distribution of UT, UII has now been shown to exert a large array of biologic activities, in particular in the CNS, the cardiovascular system, and the kidney. Here, we review the current knowledge concerning the pleiotropic actions of UII and discusses the possible use of antagonists for future therapeutic applications.
Collapse
Affiliation(s)
- Hubert Vaudry
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - Jérôme Leprince
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - David Chatenet
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - Alain Fournier
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - David G Lambert
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - Jean-Claude Le Mével
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - Eliot H Ohlstein
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - Adel Schwertani
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - Hervé Tostivint
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| | - David Vaudry
- Institut National de la Santé et de la Recherche Médicale, U982, Institute for Research and Innovation in Biomedicine, Mont-Saint-Aignan, France (H.V., J.L., D.V.), University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.V.); Institut National de la Recherche Scientifique-Institut Armand Frappier, Laval, Québec, Canada (D.C., A.F.); International Associated Laboratory Samuel de Champlain, University of Rouen, Mont-Saint-Aignan, France (H.V., J.L., D.C., A.F., D.V.); Department of Cardiovascular Sciences, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom (D.G.L.); Institut National de la Santé et de la Recherche Médicale, U1101, Laboratoire de Traitement de l'Information Médicale, Laboratoire de Neurophysiologie, Université Européenne de Bretagne, Brest, France (J.-C.L.M.); AltheRx Pharmaceuticals, Malvern, Pennsylvania (E.H.O.); Division of Cardiology, Montreal General Hospital, McGill University Health Center, Montreal, Québec, Canada (A.S.); and Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7221, Evolution des Régulations Endocriniennes, Muséum National d'Histoire Naturelle, Paris, France (H.T.)
| |
Collapse
|
114
|
Oliveira CC, van Hall T. Alternative Antigen Processing for MHC Class I: Multiple Roads Lead to Rome. Front Immunol 2015; 6:298. [PMID: 26097483 PMCID: PMC4457021 DOI: 10.3389/fimmu.2015.00298] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/22/2015] [Indexed: 12/31/2022] Open
Abstract
The well described conventional antigen-processing pathway is accountable for most peptides that end up in MHC class I molecules at the cell surface. These peptides experienced liberation by the proteasome and transport by the peptide transporter TAP. However, there are multiple roads that lead to Rome, illustrated by the increasing number of alternative processing pathways that have been reported during last years. Interestingly, TAP-deficient individuals do not succumb to viral infections, suggesting that CD8 T cell immunity is sufficiently supported by alternative TAP-independent processing pathways. To date, a diversity of viral and endogenous TAP-independent peptides have been identified in the grooves of different MHC class I alleles. Some of these peptides are not displayed by normal TAP-positive cells and we therefore called them TEIPP, for “T-cell epitopes associated with impaired peptide processing.” TEIPPs are hidden self-antigens, are derived from normal housekeeping proteins, and are processed via unconventional processing pathways. Per definition, TEIPPs are presented via TAP-independent pathways, but recent data suggest that part of this repertoire still depend on proteasome and metalloprotease activity. An exception is the C-terminal peptide of the endoplasmic reticulum (ER)-membrane-spanning ceramide synthase Trh4 that is surprisingly liberated by the signal peptide peptidase (SPP), the proteolytic enzyme involved in cleaving leader sequences. The intramembrane cleaving SPP is thereby an important contributor of TAP-independent peptides. Its family members, like the Alzheimer’s related presenilins, might contribute as well, according to our preliminary data. Finally, alternative peptide routing is an emerging field and includes processes like the unfolded protein response, the ER-associated degradation, and autophagy-associated vesicular pathways. These data convince us that there is a world to be discovered in the field of unconventional antigen processing.
Collapse
Affiliation(s)
- Cláudia C Oliveira
- Department of Clinical Oncology, Leiden University Medical Center , Leiden , Netherlands
| | - Thorbald van Hall
- Department of Clinical Oncology, Leiden University Medical Center , Leiden , Netherlands
| |
Collapse
|
115
|
Bergeron É, Zivcec M, Chakrabarti AK, Nichol ST, Albariño CG, Spiropoulou CF. Recovery of Recombinant Crimean Congo Hemorrhagic Fever Virus Reveals a Function for Non-structural Glycoproteins Cleavage by Furin. PLoS Pathog 2015; 11:e1004879. [PMID: 25933376 PMCID: PMC4416775 DOI: 10.1371/journal.ppat.1004879] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 04/13/2015] [Indexed: 01/01/2023] Open
Abstract
Crimean Congo hemorrhagic fever virus (CCHFV) is a negative-strand RNA virus of the family Bunyaviridae (genus: Nairovirus). In humans, CCHFV causes fever, hemorrhage, severe thrombocytopenia, and high fatality. A major impediment in precisely determining the basis of CCHFV’s high pathogenicity has been the lack of methodology to produce recombinant CCHFV. We developed a reverse genetics system based on transfecting plasmids into BSR-T7/5 and Huh7 cells. In our system, bacteriophage T7 RNA polymerase produced complementary RNA copies of the viral S, M, and L segments that were encapsidated with the support, in trans, of CCHFV nucleoprotein and L polymerase. The system was optimized to systematically recover high yields of infectious CCHFV. Additionally, we tested the ability of the system to produce specifically designed CCHFV mutants. The M segment encodes a polyprotein that is processed by host proprotein convertases (PCs), including the site-1 protease (S1P) and furin-like PCs. S1P and furin cleavages are necessary for producing the non-structural glycoprotein GP38, while S1P cleavage yields structural Gn. We studied the role of furin cleavage by rescuing a recombinant CCHFV encoding a virus glycoprotein precursor lacking a functional furin cleavage motif (RSKR mutated to ASKA). The ASKA mutation blocked glycoprotein precursor’s maturation to GP38, and Gn precursor’s maturation to Gn was slightly diminished. Furin cleavage was not essential for replication, as blocking furin cleavage resulted only in transient reduction of CCHFV titers, suggesting that either GP38 and/or decreased Gn maturation accounted for the reduced virion production. Our data demonstrate that nairoviruses can be produced by reverse genetics, and the utility of our system uncovered a function for furin cleavage. This viral rescue system could be further used to study the CCHFV replication cycle and facilitate the development of efficacious vaccines to counter this biological and public health threat. Crimean Congo hemorrhagic fever (CCHF) is a severe viral disease characterized by rapid-onset fever, hemorrhage, and high case fatality rates. CCHF virus (CCHFV), the causative agent of CCHF, is a negative-strand RNA virus of the family Bunyaviridae (genus Nairovirus). No specific treatments or efficacious vaccines exist to combat CCHF. To investigate molecular determinants of nairovirus pathogenesis and biology, we developed a reverse genetics system capable of generating CCHFV variants with genome sequences defined by the plasmids transfected into cells for virus recovery. Our system is the first to demonstrate that a nairovirus can be efficiently recovered from the simple transfection of plasmid DNA, paving the way for specifically editing genomes of CCHFV and other nairoviruses. Using this system, we engineered mutations blocking the cleavage of CCHFV’s non-structural glycoproteins at a motif recognized by the host protease furin. Using this furin-resistant CCHFV variant, we demonstrate that direct cleavage of the viral glycoprotein by furin results in a lag in virion production, revealing a function of these glycoproteins in efficient CCHFV replication. Our experiments highlight the utility of a reverse genetics system for developing viral variants for investigating CCHFV protein function and for rationally designing vaccine strains.
Collapse
Affiliation(s)
- Éric Bergeron
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- * E-mail:
| | - Marko Zivcec
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Ayan K. Chakrabarti
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Stuart T. Nichol
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - César G. Albariño
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Christina F. Spiropoulou
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| |
Collapse
|
116
|
Ooi TC, Raymond A, Cousins M, Favreau C, Taljaard M, Gavin C, Jolly EE, Malone S, Eapen L, Chretien M, Mbikay M, Mayne J. Relationship between testosterone, estradiol and circulating PCSK9: Cross-sectional and interventional studies in humans. Clin Chim Acta 2015; 446:97-104. [PMID: 25858546 DOI: 10.1016/j.cca.2015.03.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/25/2015] [Accepted: 03/28/2015] [Indexed: 11/26/2022]
Abstract
BACKGROUND Circulating PCSK9 levels are higher in women than men, in postmenopausal than premenopausal women, and in pregnant than non-pregnant women, suggesting that sex hormones may be related to PCSK9 levels. We have examined the relationship between serum estradiol (E2) and testosterone (T) and PCSK9, and the impact of E2 replacement therapy in women and T replacement and ablation therapy in men on circulating PCSK9. METHODS We conducted a cross-sectional study to examine the correlation between serum T (in males) and E2 (in females) and serum PCSK9. We also conducted interventional studies to examine the effect of hormonal therapy on serum PCSK9 levels. RESULTS In men, (1) serum T does not correlate with circulating PCSK9 or with LDLC in the basal state, (2) T replacement therapy does not have any effect on circulating PCSK9, and (3) T ablation therapy has mixed results. In women, (1) E2 correlates inversely with circulating PCSK9 and directly with serum LDLC, but (2) E2 replacement therapy does not have any effect on circulating PCSK9. CONCLUSIONS We demonstrate differences between men and women in the relationship of their major sex hormones with circulating PCSK9. In men, circulating PCSK9 is not related to or affected by T except for a possible effect during T ablation therapy. In women, E2 is inversely related to circulating PCSK9 but the lack of effect of E2 therapy on circulating PCSK9 suggests that the E2-related differences in PCSK9 levels may be the result of differences in receptor-mediated PCSK9 clearance through E2-induced changes rather than production of PCSK9. The studies were registered with ClinicalTrials.gov NCT00848276.
Collapse
Affiliation(s)
- T C Ooi
- Clinical Research Laboratory, Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada.
| | - A Raymond
- Clinical Research Laboratory, Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - M Cousins
- Clinical Research Laboratory, Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - C Favreau
- Clinical Research Laboratory, Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - M Taljaard
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - C Gavin
- Clinical Research Laboratory, Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - E E Jolly
- The Menopause Clinic, Shirley E. Greenberg Women's Health Centre, The Ottawa Hospital, Department of Obstetrics and Gynecology, University of Ottawa, Canada
| | - S Malone
- Division of Radiation Oncology, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada
| | - L Eapen
- Division of Radiation Oncology, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada
| | - M Chretien
- Chronic Disease Program, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada; Institut de Recherches Cliniques de Montréal, Université de Montréal, Montréal, Quebec, Canada
| | - M Mbikay
- Chronic Disease Program, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada; Institut de Recherches Cliniques de Montréal, Université de Montréal, Montréal, Quebec, Canada
| | - J Mayne
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| |
Collapse
|
117
|
Tavori H, Giunzioni I, Fazio S. PCSK9 inhibition to reduce cardiovascular disease risk: recent findings from the biology of PCSK9. Curr Opin Endocrinol Diabetes Obes 2015; 22:126-32. [PMID: 25692926 PMCID: PMC4384821 DOI: 10.1097/med.0000000000000137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE OF REVIEW Review novel insights into the biology of proprotein convertase subtilisin/kexin 9 (PCSK9) that may explain the extreme efficiency of PCSK9 inhibition and the unexpected metabolic effects resulting from PCSK9 monoclonal antibody therapy, and may identify additional patients as target of therapy. RECENT FINDINGS For over 20 years, the practical knowledge of cholesterol metabolism has centered around cellular mechanisms, and around the idea that statin therapy is the essential step to control metabolic abnormalities for cardiovascular risk management. This view has been embraced by the recent AHA/ACC guidelines, but is being challenged by recent studies including nonstatin medications and by the development of a new class of cholesterol-lowering agents that seems destined to early US Food and Drug Administration approval. The discovery of PCSK9 - a circulating protein that regulates hepatic low-density lipoprotein (LDL) receptor and serum LDL cholesterol levels - has led to a race for its therapeutic inhibition. Recent findings on PCSK9 regulation and pleiotropic effects will help identify additional patient groups likely to benefit from the inhibitory therapy and unravel the full potential of PCSK9 inhibition therapy. SUMMARY Injectable human monoclonal antibodies to block the interaction between PCSK9 and LDL receptor are demonstrating extraordinary efficacy (LDL reductions of up to 70%) and almost the absence of any side-effects. A more moderate effect is seen on other lipoprotein parameters, with the exception of lipoprotein(a) levels. We describe mechanisms that can explain the effect on lipoprotein(a), predict a potential effect on postprandial triglyderides, and suggest a new category of patients for anti-PCSK9 therapy.
Collapse
Affiliation(s)
- Hagai Tavori
- The Knight Cardiovascular Institute, Center for Preventive Cardiology, Oregon Health and Sciences University, Portland, Oregon, USA
| | | | | |
Collapse
|
118
|
Turpeinen H, Seppälä I, Lyytikäinen LP, Raitoharju E, Hutri-Kähönen N, Levula M, Oksala N, Waldenberger M, Klopp N, Illig T, Mononen N, Laaksonen R, Raitakari O, Kähönen M, Lehtimäki T, Pesu M. A genome-wide expression quantitative trait loci analysis of proprotein convertase subtilisin/kexin enzymes identifies a novel regulatory gene variant for FURIN expression and blood pressure. Hum Genet 2015; 134:627-36. [PMID: 25813623 DOI: 10.1007/s00439-015-1546-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 03/18/2015] [Indexed: 01/11/2023]
Abstract
Proprotein convertase subtilisin/kexin (PCSK) enzymes cleave and convert their immature substrates into biologically active forms. Polymorphisms in the PCSK genes have been reported to associate with human diseases and phenotypes, including hypercholesterolemia and blood pressure (BP), and targeting PCSKs is considered a promising future form of drug therapy. PCSK processing is readily induced upon upregulation of the enzyme, but the genetic factors contributing to PCSK expression have not been thoroughly characterized. To gain a comprehensive understanding of the genetic regulation of PCSK expression, we performed, for the first time, a genome-wide expression quantitative trait loci (eQTL) analysis using mRNA expression in >1400 human peripheral blood samples from the Cardiovascular Risk in Young Finns Study and ca. ten million single-nucleotide polymorphisms (SNPs). The expression data showed clear expression for FURIN, PCSK5, PCSK7 and MBTPS1 (membrane-bound transcription factor peptidase, site 1) mRNAs in virtually all tested samples. A discovery analysis demonstrated a genome-wide significant (p < 5 × 10(-8)) association with the selected PCSK probes for 1024 variants, which were located at ten independent loci. Of these loci, 5/10 could be confirmed to regulate PCSK expression in two additional and independent sample sets. Finally, a phenotypic analysis demonstrated that a novel cis-eQTL SNP rs4702 for FURIN is strongly associated with both diastolic (p = 0.012) and systolic (p = 0.035) BP levels, as well as peripheral vascular resistance (p = 0.003). These findings indicate that the expression of the PCSK enzymes is regulated by genetic factors, which have biological roles in health and disease.
Collapse
Affiliation(s)
- Hannu Turpeinen
- BioMediTech, University of Tampere, Biokatu 8, 33580, Tampere, Finland,
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
119
|
Basak A, Goswami M, Rajkumar A, Mitra T, Majumdar S, O'Reilly P, Bdour HM, Trudeau VL, Basak A. Enediynyl peptides and iso-coumarinyl methyl sulfones as inhibitors of proprotein convertases PCSK8/SKI-1/S1P and PCSK4/PC4: Design, synthesis and biological evaluations. Bioorg Med Chem Lett 2015; 25:2225-37. [PMID: 25881830 DOI: 10.1016/j.bmcl.2015.03.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/09/2015] [Accepted: 03/11/2015] [Indexed: 02/05/2023]
Abstract
The proprotein convertases PCSK8 and PCSK4 are, respectively, the 8th and 4th members of Ca(+2)-dependent serine endoprotease of Proprotein Convertase Subtilisin Kexin (PCSK) super family structurally related to the bacterial subtilisin and yeast kexin. The membrane bound PCSK8 (also called SKI-1 or S1P) is implicated in sterol regulation and lipid synthesis via its role in the maturation of human (h) SREBP-2. It also plays role in cartilage formation, bone mineralization, as well as viral pathogenesis. On the other hand, PCSK4 has been linked to mammalian fertilization and placenta growth. Owing to these findings, interest has grown to develop specific inhibitors against these enzymes for potential biochemical and therapeutic applications. In this study we developed two types of small molecule inhibitors of PCSK8 and PCSK4 and demonstrated their anti-proteolytic activities in vitro cell-free and in vitro cell culture systems. These are isocoumarinyl methyl sulfone derivatives and enediyne amino acid containing peptides. Our in vitro data suggested that one of the 7 sulfone derivatives (methyl phenyl sulfone) inhibited PCSK8 with inhibition constant Ki ∼255μM. It also blocked PCSK8-mediated processing of hSREBP-2 in HepG2 cell in a concentration-dependent manner. However all 7 iso-coumarinyl methyl sulfones inhibited htrypsin with IC50 ranging from 2 to 165μM. In contrast, all our designed enediynyl peptides inhibited PCSK8 and PCSK4 activity with Ki and IC50 in low μM or high nM ranges. All compounds exhibited competitive inhibition as indicated by their enzyme kinetic plots and observed dependence of IC50 value on substrate concentration. Our study confirmed that incorporation at the substrate cleavage site of 'Enediyne amino acid' generates potent inhibitors of PCSK8 and PCSK4. This represents a novel approach for future development of inhibitors of PCSK or other enzymes.
Collapse
Affiliation(s)
- Ajoy Basak
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, U Ottawa, Canada.
| | - Mukunda Goswami
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada; Centre for Advanced Research in Environmental Genomics, Department of Biology, U Ottawa, Canada
| | - Abishankari Rajkumar
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Tapobrata Mitra
- Department of Chemistry, Indian Institute of Technology, Kharagpur, W Bengal, India
| | - Swapan Majumdar
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada; Chemistry Department, Tripura University, Suryamaninagar 799022, India
| | - Paul O'Reilly
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | | | - Vance L Trudeau
- Centre for Advanced Research in Environmental Genomics, Department of Biology, U Ottawa, Canada
| | - Amit Basak
- Department of Chemistry, Indian Institute of Technology, Kharagpur, W Bengal, India
| |
Collapse
|
120
|
Alghamdi RH, O'Reilly P, Lu C, Gomes J, Lagace TA, Basak A. LDL-R promoting activity of peptides derived from human PCSK9 catalytic domain (153-421): design, synthesis and biochemical evaluation. Eur J Med Chem 2015; 92:890-907. [PMID: 25679794 DOI: 10.1016/j.ejmech.2015.01.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 01/09/2015] [Accepted: 01/10/2015] [Indexed: 01/31/2023]
Abstract
BACKGROUND High level of Low Density Lipoprotein-Cholesterol (LDL-C) in circulation in the blood is associated with an elevated risk of cardiovascular disease (CVD) and stroke. Currently the statin drugs which inhibit the enzyme HMG-CoA reductase responsible for cholesterol synthesis in the liver are very effective in lowering LDL-cholesterol. However these drugs are often associated with serious side effects particularly for ∼10-12% of cases. Therefore there is a need to develop non-statin based cholesterol reducing agents. Recently it was revealed that the secreted Proprotein Convertase Subtilisin Kexin 9 (PCSK9) binds with LDL-receptor (LDL-R) causing its degradation in the lysosome with the result of LDL-C accumulating in the blood. Thus PCSK9 has become an alternative target for development of non-statin cholesterol reducing agents. It is established that the catalytic domain of PCSK9 (aa153-421) and the EGF-A domain of LDL-R (aa314-355) are involved in the above bind leading to the reduction of LDL-R level and accumulation of LDL-C. OBJECTIVE The major goal of this study is to identify peptide/s from the catalytic domain of hPCSK9 that can block the binding of hPCSK9 and LDL-R and therefore can reduce LDL-R degradation leading to the clearance of LDL-C from the plasma. RESULTS Using 51 synthetic linear peptides (P1-P51) of 15aa long with 10 amino acids overlapping sequences spanning the entire catalytic segment of hPCSK9 (aa153-421), we identified two domains of hPCSK9 namely (aa323-358) and (aa365-384) that exhibited strong binding affinity towards synthetic EGF-A peptide. The results were based on mass spectrometry, fluorescence spectroscopy and native gel electrophoresis. Thus peptides containing the above segments in part (P35-P39 and P42-P47) exhibited LDL-R promoting activity when added exogenously to culture medium of growing human hepatic cells like HepG2 and HuH7. The effects were particularly significant with peptides P36, P37, P46 and P47. Interestingly, the first two peptides are present within the disulphide loop Cys(323)-Cys(358) and contain the key gain of function mutation D(374)/Y site while the last two peptides contain another disulphide bridge loop Cys(375)-Cys(378) and the second most potent gain of function mutation R(357)/H. Further studies revealed that S-S bridged cyclic loop peptide hPCSK9(365-384) exhibited the highest (∼3.5-fold) LDL-R promoting activity in both HepG2 and HuH7 when applied at 5 μM concentration level. This effect is completely abrogated when one of the Cys residues is substituted by Ala thereby preventing any S-S bond formation. This suggested its critical role in the bioactivity. It is proposed that LDL-R promoting activity of this and other selected PCSK9 catalytic peptides such as P36, P37, P46 and P47 are most likely mediated via intervention of PCSK9:LDL-R complex formation. Our findings may find useful application in future development of small molecule PCSK9 inhibitors for intervention of hypercholesterolemia and associated cardiovascular disease.
Collapse
Affiliation(s)
- Rasha H Alghamdi
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Paul O'Reilly
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Chunyu Lu
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - James Gomes
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Thomas A Lagace
- Lipoprotein Receptor Biology Laboratory, Department of Pathology and Laboratory Medicine, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON K1Y 4W7, Canada
| | - Ajoy Basak
- Interdisciplinary School of Health Sciences Unit, Faculty of Health Science, U Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada; Chronic Disease Program, Ottawa Hospital Research Institute, U Ottawa, 725 Parkdale Ave, Ottawa, ON K1Y4E9, Canada.
| |
Collapse
|
121
|
Group 2 innate lymphoid cells promote beiging of white adipose tissue and limit obesity. Nature 2014; 519:242-6. [PMID: 25533952 DOI: 10.1038/nature14115] [Citation(s) in RCA: 737] [Impact Index Per Article: 73.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 11/27/2014] [Indexed: 12/12/2022]
Abstract
Obesity is an increasingly prevalent disease regulated by genetic and environmental factors. Emerging studies indicate that immune cells, including monocytes, granulocytes and lymphocytes, regulate metabolic homeostasis and are dysregulated in obesity. Group 2 innate lymphoid cells (ILC2s) can regulate adaptive immunity and eosinophil and alternatively activated macrophage responses, and were recently identified in murine white adipose tissue (WAT) where they may act to limit the development of obesity. However, ILC2s have not been identified in human adipose tissue, and the mechanisms by which ILC2s regulate metabolic homeostasis remain unknown. Here we identify ILC2s in human WAT and demonstrate that decreased ILC2 responses in WAT are a conserved characteristic of obesity in humans and mice. Interleukin (IL)-33 was found to be critical for the maintenance of ILC2s in WAT and in limiting adiposity in mice by increasing caloric expenditure. This was associated with recruitment of uncoupling protein 1 (UCP1)(+) beige adipocytes in WAT, a process known as beiging or browning that regulates caloric expenditure. IL-33-induced beiging was dependent on ILC2s, and IL-33 treatment or transfer of IL-33-elicited ILC2s was sufficient to drive beiging independently of the adaptive immune system, eosinophils or IL-4 receptor signalling. We found that ILC2s produce methionine-enkephalin peptides that can act directly on adipocytes to upregulate Ucp1 expression in vitro and that promote beiging in vivo. Collectively, these studies indicate that, in addition to responding to infection or tissue damage, ILC2s can regulate adipose function and metabolic homeostasis in part via production of enkephalin peptides that elicit beiging.
Collapse
|
122
|
Milionis H, Liamis G, Elisaf M. Proprotein convertase subtilisin kexin 9 inhibitors: next generation in lipid-lowering therapy. Expert Opin Biol Ther 2014; 15:287-98. [DOI: 10.1517/14712598.2015.984682] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
123
|
Binding of MAGP2 to microfibrils is regulated by proprotein convertase cleavage. Matrix Biol 2014; 40:27-33. [DOI: 10.1016/j.matbio.2014.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/06/2014] [Accepted: 08/08/2014] [Indexed: 11/22/2022]
|
124
|
Ng M, Ndungo E, Jangra RK, Cai Y, Postnikova E, Radoshitzky SR, Dye JM, Ramírez de Arellano E, Negredo A, Palacios G, Kuhn JH, Chandran K. Cell entry by a novel European filovirus requires host endosomal cysteine proteases and Niemann-Pick C1. Virology 2014; 468-470:637-646. [PMID: 25310500 PMCID: PMC4252868 DOI: 10.1016/j.virol.2014.08.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 07/30/2014] [Accepted: 08/20/2014] [Indexed: 11/19/2022]
Abstract
Lloviu virus (LLOV), a phylogenetically divergent filovirus, is the proposed etiologic agent of die-offs of Schreibers's long-fingered bats (Miniopterus schreibersii) in western Europe. Studies of LLOV remain limited because the infectious agent has not yet been isolated. Here, we generated a recombinant vesicular stomatitis virus expressing the LLOV spike glycoprotein (GP) and used it to show that LLOV GP resembles other filovirus GP proteins in structure and function. LLOV GP must be cleaved by endosomal cysteine proteases during entry, but is much more protease-sensitive than EBOV GP. The EBOV/MARV receptor, Niemann-Pick C1 (NPC1), is also required for LLOV entry, and its second luminal domain is recognized with high affinity by a cleaved form of LLOV GP, suggesting that receptor binding would not impose a barrier to LLOV infection of humans and non-human primates. The use of NPC1 as an intracellular entry receptor may be a universal property of filoviruses.
Collapse
Affiliation(s)
- Melinda Ng
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Esther Ndungo
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Rohit K Jangra
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Yingyun Cai
- Integrated Research Facility at Fort Detrick, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, United States
| | - Elena Postnikova
- Integrated Research Facility at Fort Detrick, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, United States
| | - Sheli R Radoshitzky
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, United States
| | - John M Dye
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, United States
| | | | - Ana Negredo
- National Center of Microbiology, Instituto de Salud Carlos III, 28220 Madrid, Spain
| | - Gustavo Palacios
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, United States
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, United States
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
| |
Collapse
|
125
|
Oksanen A, Aittomäki S, Jankovic D, Ortutay Z, Pulkkinen K, Hämäläinen S, Rokka A, Corthals GL, Watford WT, Junttila I, O'Shea JJ, Pesu M. Proprotein convertase FURIN constrains Th2 differentiation and is critical for host resistance against Toxoplasma gondii. THE JOURNAL OF IMMUNOLOGY 2014; 193:5470-9. [PMID: 25355923 DOI: 10.4049/jimmunol.1401629] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The proprotein convertase subtilisin/kexin enzymes proteolytically convert immature proproteins into bioactive molecules, and thereby they serve as key regulators of cellular homeostasis. The archetype proprotein convertase subtilisin/kexin, FURIN, is a direct target gene of the IL-12/STAT4 pathway and it is upregulated in Th1 cells. We have previously demonstrated that FURIN expression in T cells critically regulates the maintenance of peripheral immune tolerance and the functional maturation of pro-TGF-β1 in vivo, but FURIN's role in cell-mediated immunity and Th polarization has remained elusive. In this article, we show that T cell-expressed FURIN is essential for host resistance against a prototypic Th1 pathogen, Toxoplasma gondii, and for the generation of pathogen-specific Th1 lymphocytes, including Th1-IL-10 cells. FURIN-deficient Th cells instead show elevated expression of IL-4R subunit α on cell surface, sensitized IL-4/STAT6 signaling, and a propensity to polarize toward the Th2 phenotype. By exploring FURIN-interacting proteins in Jurkat T cells with Strep-Tag purification and mass spectrometry, we further identify an association with a cytoskeleton modifying Ras-related C3 botulinum toxin substrate/dedicator of cytokinesis 2 protein complex and unravel that FURIN promotes F-actin polymerization, which has previously been shown to downregulate IL-4R subunit α cell surface expression and promote Th1 responses. In conclusion, our results demonstrate that in addition to peripheral immune tolerance, T cell-expressed FURIN is also a central regulator of cell-mediated immunity and Th1/2 cell balance.
Collapse
Affiliation(s)
- Anna Oksanen
- Laboratory of Immunoregulation, BioMediTech, University of Tampere, 33014 Tampere, Finland
| | - Saara Aittomäki
- Laboratory of Immunoregulation, BioMediTech, University of Tampere, 33014 Tampere, Finland
| | - Dragana Jankovic
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Zsuzsanna Ortutay
- Laboratory of Immunoregulation, BioMediTech, University of Tampere, 33014 Tampere, Finland
| | - Kati Pulkkinen
- Laboratory of Immunoregulation, BioMediTech, University of Tampere, 33014 Tampere, Finland
| | - Sanna Hämäläinen
- Laboratory of Immunoregulation, BioMediTech, University of Tampere, 33014 Tampere, Finland
| | - Anne Rokka
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Garry L Corthals
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland; Van't Hoff Institute for Molecular Sciences, University of Amsterdam, 1090 GD Amsterdam, the Netherlands
| | - Wendy T Watford
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892; Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602
| | - Ilkka Junttila
- Fimlab Laboratories, Pirkanmaa Hospital District, 33101 Tampere, Finland; School of Medicine, University of Tampere, 33014 Tampere, Finland; and
| | - John J O'Shea
- Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Marko Pesu
- Laboratory of Immunoregulation, BioMediTech, University of Tampere, 33014 Tampere, Finland; Fimlab Laboratories, Pirkanmaa Hospital District, 33101 Tampere, Finland; Department of Dermatology, Pirkanmaa Hospital District, 33101 Tampere, Finland
| |
Collapse
|
126
|
Abstract
PURPOSE OF REVIEW Proprotein convertase subtilisin/kexin type-9 (PCSK9) binds to LDL receptor (LDLR) and targets it for lysosomal degradation in cells. Decreased hepatic clearance of plasma LDL-cholesterol is the primary gauge of PCSK9 activity in humans; however, PCSK9's evolutionary role may extend to other lipoprotein classes and processes. This review highlights studies that are providing novel insights into physiological regulation of PCSK9 transcription and plasma PCSK9 activity. RECENT FINDINGS Recent studies indicate that circulating PCSK9 binds to apolipoprotein B100 on LDL particles, which in turn inhibits PCSK9's ability to bind to cell surface LDLRs. Negative feedback of secreted PCSK9 activity by LDL could serve to increase plasma excursion of triglyceride-rich lipoproteins and monitor lipoprotein remodeling. Recent findings have identified hepatocyte nuclear factor-1α as a key transcriptional regulator that cooperates with sterol regulatory element-binding protein-2 to control PCSK9 expression in hepatocytes in response to nutritional and hormonal inputs, as well as acute inflammation. SUMMARY PCSK9 is an established target for cholesterol-lowering therapies. Further study of PCSK9 regulatory mechanisms may identify additional control points for pharmacological inhibition of PCSK9-mediated LDLR degradation. PCSK9 function could reflect ancient roles in the fasting-feeding cycle and in linking lipoprotein metabolism with innate immunity.
Collapse
Affiliation(s)
- Thomas A Lagace
- Department of Pathology and Laboratory Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| |
Collapse
|
127
|
Abstract
From proglucagon, at least six final biologically active peptides are produced by tissue-specific post-translational processing. While glucagon and GLP-1 are the subject of permanent studies, the four others are usually left in the shadow, in spite of their large biological interest. The present review is devoted to oxyntomodulin and miniglucagon, not forgetting glicentin, although much less is known about it. Oxyntomodulin (OXM) and glicentin are regulators of gastric acid and hydromineral intestinal secretions. OXM is also deeply involved in the control of food intake and energy expenditure, properties that make this peptide a credible treatment of obesity if the question of administration is solved, as for any peptide. Miniglucagon, the C-terminal undecapeptide of glucagon which results from a secondary processing of original nature, displays properties antagonistic to that of the mother-hormone glucagon: (a) it inhibits glucose-, glucagon- and GLP-1-stimulated insulin release at sub-picomolar concentrations, (b) it reduces the in vivo insulin response to glucose with no change in glycemia, (c) it displays insulin-like properties at the cellular level using only a part of the pathway used by insulin, making it a good basis for developing a pharmacological workaround of insulin resistance.
Collapse
Affiliation(s)
| | - Stéphane Dalle
- INSERM, Research-Pathophysiology of the Pancreatic β Cell, Institute of Functional Genomic, INSERM U 661, CNRS UMR 5203, Universities Montpellier 1 & 2, Montpellier, France.
| |
Collapse
|
128
|
Chorba JS, Shokat KM. The proprotein convertase subtilisin/kexin type 9 (PCSK9) active site and cleavage sequence differentially regulate protein secretion from proteolysis. J Biol Chem 2014; 289:29030-43. [PMID: 25210046 DOI: 10.1074/jbc.m114.594861] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Biologic-based strategies to inhibit proprotein convertase subtilisin/kexin type 9 (PCSK9) show promise as anti-hypercholesterolemic and, therefore, anti-atherosclerotic therapies. Despite substantial effort, no small molecule strategy to inhibit PCSK9 has demonstrated feasibility. In this study we interrogated the chemistry of the PCSK9 active site and its adjacent residues to identify a foothold with which to drug the PCSK9 processing pathway and ultimately disrupt the interaction with the LDL receptor. Here, we develop a system in which we amplify the readout of PCSK9 proteolysis with a highly specific substrate in cells, showing that the PCSK9 catalytic domain is capable of proteolysis in trans. We use this system to show that the substrate specificity for PCSK9 proteolysis is distinct from the specificity for PCSK9 secretion, demonstrating that PCSK9 processing occurs in two separate sequential steps: that of proteolysis followed by secretion. We show that specific residues in the protease recognition sequence can differentially modulate the effects on proteolysis and secretion. Additionally, we demonstrate that the clinically described, dominant negative Q152H mutation restricts proteolysis and secretion independently. Our results suggest that the PCSK9 active site and its adjacent residues serve as an allosteric modulator of protein secretion independent of its role in proteolysis, revealing a new strategy for intracellular PCSK9 inhibition.
Collapse
Affiliation(s)
- John S Chorba
- From the Division of Cardiology, San Francisco General Hospital, Department of Medicine, University of California, San Francisco, California 94110, Cardiovascular Research Institute, University of California, San Francisco, California 94158, and
| | - Kevan M Shokat
- Cardiovascular Research Institute, University of California, San Francisco, California 94158, and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158 and Department of Chemistry, University of California, Berkeley, California 94720
| |
Collapse
|
129
|
Is there a link between proprotein convertase PC7 activity and human lipid homeostasis? FEBS Open Bio 2014; 4:741-5. [PMID: 25349778 PMCID: PMC4208093 DOI: 10.1016/j.fob.2014.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/08/2014] [Accepted: 08/26/2014] [Indexed: 11/23/2022] Open
Abstract
A R504H mutation in human proprotein convertase PC7 is associated with increased HDL and reduced triglycerides. Wild-type PC7 and its R504H mutant have identical cellular enzymatic activities. In situ hybridization revealed co-localization of mouse ApoF and PC7 mRNAs in liver. WT and PC7 KO mice do not exhibit changes in circulating levels of insulin or glucose. WT and PC7 KO mice do not exhibit changes in circulating levels of HDL, TG and LDL.
A genome-wide association study suggested that a R504H mutation in the proprotein convertase PC7 is associated with increased circulating levels of HDL and reduced triglycerides in black Africans. Our present results show that PC7 and PC7-R504H exhibit similar processing of transferrin receptor-1, proSortilin, and apolipoprotein-F. Plasma analyses revealed no change in the lipid profiles, insulin or glucose of wild type and PC7 KO mice. Thus, the R504H mutation does not modify the proteolytic activity of PC7. The mechanisms behind the implication of PC7 in the regulation of human HDL, triglycerides and in modifying the levels of atherogenic small dense LDL remain to be elucidated.
Collapse
Key Words
- ANGPTL3, angiopoietin-like 3
- ANGPTL4, angiopoietin-like 4
- ApoF, apolipoprotein-F
- Apolipoprotein F
- GOF, gain of function
- GWAS, genome-wide association study
- HDL, high-density lipoprotein
- HDL/LDL
- KO, knockout
- LDL, low-density lipoprotein
- PCs, proprotein convertases
- Proprotein convertase PC7
- SNP, single nucleotide polymorphism
- Sortilin
- TGN, trans Golgi network
- TMD, transmembrane domain
- Transferrin receptor 1
- Triglycerides
- VLDL, very low-density lipoprotein
- hTfR1, human PC7-substrates: transferrin receptor 1
Collapse
|
130
|
Hepatic overexpression of the prodomain of furin lessens progression of atherosclerosis and reduces vascular remodeling in response to injury. Atherosclerosis 2014; 236:121-30. [PMID: 25026302 DOI: 10.1016/j.atherosclerosis.2014.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 06/16/2014] [Accepted: 06/18/2014] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Atherosclerosis is a complex disease, involving elevated LDL-c, lipid accumulation in the blood vessel wall, foam cell formation and vascular dysfunction. Lowering plasma LDL-c is the cornerstone of current management of cardiovascular disease. However, new approaches which reduce plasma LDL-c and lessen the pathological vascular remodeling occurring in the disease should also have therapeutic value. Previously, we found that overexpression of profurin, the 83-amino acid prodomain of the proprotein convertase furin, lowered plasma HDL levels in wild-type mice. The question that remained was whether it had effects on apolipoprotein B (ApoB)-containing lipoproteins. METHODS Adenovirus mediated overexpression of hepatic profurin in Ldlr(-/-)mice and wild-type mice were used to evaluate effects of profurin on ApoB-containing lipoproteins, atherosclerosis and vascular remodeling. RESULTS Hepatic profurin overexpression resulted in a significant reduction in atherosclerotic lesion development in Ldlr(-/-)mice and a robust reduction in plasma LDL-c. Metabolic studies revealed lower secretion of ApoB and triglycerides in VLDL particles. Mechanistic studies showed that in the presence of profurin, hepatic ApoB, mainly ApoB100, was degraded by proteasomes. There was no effect on ApoB mRNA expression. Importantly, short-term hepatic profurin overexpression did not result in hepatic lipid accumulation. Blood vessel wall thickening caused by either wire-induced femoral artery injury or common carotid artery ligation was reduced. Profurin expression inhibited proliferation and migration in vascular smooth muscle cells in vitro. CONCLUSION These results indicate that a profurin-based therapy has the potential to treat atherosclerosis by improving metabolic lipid profiles and reducing both atherosclerotic lesion development and pathological vascular remodeling.
Collapse
|
131
|
Dhanvantari S. The genetics of obesity meets basic cell biology through prohormone convertase 1/3. Endocrinology 2014; 155:2343-5. [PMID: 24950989 DOI: 10.1210/en.2014-1376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
132
|
Dragan S, Serban MC, Banach M. Proprotein convertase subtilisin/kexin 9 inhibitors: an emerging lipid-lowering therapy? J Cardiovasc Pharmacol Ther 2014; 20:157-68. [PMID: 24938457 DOI: 10.1177/1074248414539562] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Proprotein convertase subtilisin/kexin 9 (PCSK9) is part of the proteinase K subfamily of subtilases and plays a key role in lipid metabolism. It increases degradation of the low-density lipoprotein receptor (LDL-R), modulates cholesterol metabolism and transport, and contributes to the production of apolipoprotein B (apoB) in intestinal cells. Exogenous PCSK9 modifies the activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase and acyl coenzyme A:cholesterol acyltransferase and enhances secretion of chylomicrons by modulating production of lipids and apoB-48. Statins increase PCSK9 messenger RNA expression and attenuate the capacity to increase LDL-R levels. Therefore, the inhibition of PCSK9 in combination with statins provides a promising approach for lowering low-density lipoprotein cholesterol (LDL-C) concentrations. This review will address new therapeutic strategies targeting PCSK9, including monoclonal antibodies, antisense oligonucleotides, small interfering RNAs, and other small molecule inhibitors. Further studies are still needed to determine the efficacy and safety of the PCSK9 inhibitors not only to decrease LDL-C but also to investigate the potential underlying mechanisms involved and to test whether these compounds actually reduce cardiovascular end points and mortality.
Collapse
Affiliation(s)
- Simona Dragan
- Department of Cardiology, University of Medicine and Pharmacy "Victor Babes" Timisoara, Timisoara, Romania Center for Interdisciplinary Research, University of Medicine and Pharmacy "Victor Babes" Timisoara, Timisoara, Romania
| | - Maria-Corina Serban
- Center for Interdisciplinary Research, University of Medicine and Pharmacy "Victor Babes" Timisoara, Timisoara, Romania Department of Functional Sciences, Chair of Pathophysiology, University of Medicine and Pharmacy "Victor Babes" Timisoara, Timisoara, Romania
| | - Maciej Banach
- Department of Hypertension, Chair of Nephrology and Hypertension, Medical University of Lodz, Poland
| |
Collapse
|
133
|
Van Roey K, Uyar B, Weatheritt RJ, Dinkel H, Seiler M, Budd A, Gibson TJ, Davey NE. Short Linear Motifs: Ubiquitous and Functionally Diverse Protein Interaction Modules Directing Cell Regulation. Chem Rev 2014; 114:6733-78. [DOI: 10.1021/cr400585q] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kim Van Roey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bora Uyar
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Robert J. Weatheritt
- MRC
Laboratory of Molecular Biology (LMB), Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Holger Dinkel
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Markus Seiler
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Aidan Budd
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Toby J. Gibson
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Norman E. Davey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Department
of Physiology, University of California, San Francisco, San Francisco, California 94143, United States
| |
Collapse
|
134
|
Abstract
Since the discovery of proprotein convertase subtilisin kexin 9 (PCSK9) in 2003, this PC has attracted a lot of attention from the scientific community and pharmaceutical companies. Secreted into the plasma by the liver, the proteinase K-like serine protease PCSK9 binds the low-density lipoprotein (LDL) receptor at the surface of hepatocytes, thereby preventing its recycling and enhancing its degradation in endosomes/lysosomes, resulting in reduced LDL-cholesterol clearance. Surprisingly, in a nonenzymatic fashion, PCSK9 enhances the intracellular degradation of all its target proteins. Rare gain-of-function PCSK9 variants lead to higher levels of LDL-cholesterol and increased risk of cardiovascular disease; more common loss-of-function PCSK9 variants are associated with reductions in both LDL-cholesterol and risk of cardiovascular disease. It took 9 years to elaborate powerful new PCSK9-based therapeutic approaches to reduce circulating levels of LDL-cholesterol. Presently, PCSK9 monoclonal antibodies that inhibit its function on the LDL receptor are evaluated in phase III clinical trials. This review will address the biochemical, genetic, and clinical aspects associated with PCSK9's biology and pathophysiology in cells, rodent and human, with emphasis on the clinical benefits of silencing the expression/activity of PCSK9 as a new modality in the treatment of hypercholesterolemia and associated pathologies.
Collapse
Affiliation(s)
- Nabil G Seidah
- From the Laboratories of Biochemical Neuroendocrinology (N.G.S., Z.A.) and Functional Endoproteolysis (M.C., M.M.), Institut de Recherches Cliniques de Montréal, affiliated to the Université de Montréal, Montréal, Quebec, Canada; and Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada (M.C., M.M.)
| | | | | | | |
Collapse
|
135
|
Shao W, Espenshade PJ. Sterol regulatory element-binding protein (SREBP) cleavage regulates Golgi-to-endoplasmic reticulum recycling of SREBP cleavage-activating protein (SCAP). J Biol Chem 2014; 289:7547-57. [PMID: 24478315 DOI: 10.1074/jbc.m113.545699] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Sterol regulatory element-binding protein (SREBP) transcription factors are central regulators of cellular lipogenesis. Release of membrane-bound SREBP requires SREBP cleavage-activating protein (SCAP) to escort SREBP from the endoplasmic reticulum (ER) to the Golgi for cleavage by site-1 and site-2 proteases. SCAP then recycles to the ER for additional rounds of SREBP binding and transport. Mechanisms regulating ER-to-Golgi transport of SCAP-SREBP are understood in molecular detail, but little is known about SCAP recycling. Here, we have demonstrated that SCAP Golgi-to-ER transport requires cleavage of SREBP at site-1. Reductions in SREBP cleavage lead to SCAP degradation in lysosomes, providing additional negative feedback control to the SREBP pathway. Current models suggest that SREBP plays a passive role prior to cleavage. However, we show that SREBP actively prevents premature recycling of SCAP-SREBP until initiation of SREBP cleavage. SREBP regulates SCAP in human cells and yeast, indicating that this is an ancient regulatory mechanism.
Collapse
Affiliation(s)
- Wei Shao
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | | |
Collapse
|
136
|
Fu J, Zhang J, Gong Y, Testa CL, Klein-Szanto AJ. Regulation of HIF-1 alpha by the proprotein convertases furin and PC7 in human squamous carcinoma cells. Mol Carcinog 2014; 54:698-706. [PMID: 24436242 DOI: 10.1002/mc.22131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 12/02/2013] [Accepted: 12/19/2013] [Indexed: 02/04/2023]
Abstract
Proprotein convertases (PC), a family of serine proteases, process cancer-related substrates such as growth factors, growth factor receptors, cell adhesion molecules, metalloproteinases, etc. HIF-1α is a major transcription factor involved in tumorigenesis by sensing intratumoral hypoxia. Furin (PCSK3) is one of the numerous target genes regulated by HIF-1α transactivation and its distribution into endosomal compartments and onto the cell surface can be triggered by hypoxia via HIF-1α. siRNAs to knockdown PCs were transfected into cells alone or in combination with different drug treatments. Protein and RNA expression levels were analyzed by Western blotting or RT-PCR, respectively. PC7 (PCSK7) and furin siRNAs upregulated HIF-1α protein under normoxic condition to a level similar to that obtained by cobalt chloride treatment, eventually leading to activation of VEGF-A synthesis in two human head and neck squamous cell carcinoma cell lines. The unchanged levels of HIF-1α mRNA expression under siRNA treatment and the additive HIF-1α induction of PC siRNAs and either cobalt chloride or the 26S ribosome inhibitor, MG-132, suggested a post-transcriptional PC-mediated regulation. Furthermore, cycloheximide chase showed that PC7/furin siRNA regulation occurred at the level of HIF-1α translation. A specific IGF-1R signaling inhibitor was able to attenuate the PC siRNA induction of HIF-1α, suggesting the involvement of the IGF-1R pathway. Thus, the data show that PCs regulate HIF-1α. Furin and PC7 siRNAs induced HIF-1α protein by increasing its translation, resulting in upregulation of VEGF-A. This finding may provide insight into intricate PC functions that seem to be independent from their substrate-processing activity.
Collapse
Affiliation(s)
- Jian Fu
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania.,Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Jirong Zhang
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania.,Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Yulan Gong
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Courtney Lyons Testa
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania.,Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Andres J Klein-Szanto
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania.,Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| |
Collapse
|
137
|
Turpeinen H, Ortutay Z, Pesu M. Genetics of the first seven proprotein convertase enzymes in health and disease. Curr Genomics 2014; 14:453-67. [PMID: 24396277 PMCID: PMC3867721 DOI: 10.2174/1389202911314050010] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/13/2013] [Accepted: 09/14/2013] [Indexed: 12/16/2022] Open
Abstract
Members of the substilisin/kexin like proprotein convertase (PCSK) protease family cleave and convert immature pro-proteins into their biologically active forms. By cleaving for example prohormones, cytokines and cell membrane proteins, PCSKs participate in maintaining the homeostasis in a healthy human body. Conversely, erratic enzymatic function is thought to contribute to the pathogenesis of a wide variety of diseases, including obesity and hypercholestrolemia. The first characterized seven PCSK enzymes (PCSK1-2, FURIN, PCSK4-7) process their substrates at a motif made up of paired basic amino acid residues. This feature results in a variable degree of biochemical redundancy in vitro, and consequently, shared substrate molecules between the different PCSK enzymes. This redundancy has confounded our understanding of the specific biological functions of PCSKs. The physiological roles of these enzymes have been best illustrated by the phenotypes of genetically engineered mice and patients that carry mutations in the PCSK genes. Recent developments in genome-wide methodology have generated a large amount of novel information on the genetics of the first seven proprotein convertases. In this review we summarize the reported genetic alterations and their associated phenotypes.
Collapse
Affiliation(s)
- Hannu Turpeinen
- Immunoregulation, Institute of Biomedical Technology, University of Tampere, and BioMediTech, Tampere, Finland
| | - Zsuzsanna Ortutay
- Immunoregulation, Institute of Biomedical Technology, University of Tampere, and BioMediTech, Tampere, Finland
| | - Marko Pesu
- Immunoregulation, Institute of Biomedical Technology, University of Tampere, and BioMediTech, Tampere, Finland; ; Fimlab laboratories, Pirkanmaa Hospital District, Finland
| |
Collapse
|
138
|
Farnier M. PCSK9: From discovery to therapeutic applications. Arch Cardiovasc Dis 2013; 107:58-66. [PMID: 24373748 DOI: 10.1016/j.acvd.2013.10.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 10/25/2013] [Accepted: 10/29/2013] [Indexed: 12/11/2022]
Abstract
The proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates cholesterol metabolism mainly by targeting the low-density lipoprotein receptor (LDLR) for degradation in the liver. Gain-of-function mutations in PCSK9 are one of the genetic causes of autosomal dominant hypercholesterolaemia. Conversely, loss-of-function mutations are associated with lower concentrations of LDL cholesterol (LDL-C) and reduced coronary heart disease. As these loss-of-function mutations are not associated with apparent deleterious effects, PCSK9 inhibition is an attractive new strategy for lowering LDL-C concentration. Among the various approaches to PCSK9 inhibition, human data are only available for inhibition of PCSK9 binding to LDLR by monoclonal antibodies. In phase II studies, the two most advanced monoclonal antibodies in development (alirocumab and evolocumab) decreased atherogenic lipoproteins very effectively and were well tolerated. A dramatic decrease in LDL-C up to 70% can be obtained with the most efficacious doses. Efficacy has been evaluated so far in addition to statins in hypercholesterolaemic patients with or without familial hypercholesterolaemia, in patients with intolerance to statin therapy and in monotherapy. Large phase III programmes are ongoing to evaluate the long-term efficacy and safety of these very promising new agents.
Collapse
Affiliation(s)
- Michel Farnier
- Point médical, rond point de la nation, 21000 Dijon, France.
| |
Collapse
|
139
|
Kwok SC, Chakraborty D, Soares MJ, Dai G. Relative expression of proprotein convertases in rat ovaries during pregnancy. J Ovarian Res 2013; 6:91. [PMID: 24330629 PMCID: PMC3874651 DOI: 10.1186/1757-2215-6-91] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 12/06/2013] [Indexed: 11/29/2022] Open
Abstract
Background Proprotein convertases are a family of serine proteinases that are related to bacterial subtilisin and yeast kexin. They are involved in posttranslational processing of the precursors of a vast number of cellular proteins. With the exception of PC1/3, the relative expression levels of the proprotein convertases in the ovary during pregnancy have not been reported. The purpose of this study is to determine by real-time PCR the relative expression levels of all nine proprotein convertases in rat ovaries during pregnancy and at 3 days postpartum. Methods RNA was extracted from ovaries at Day 0, 4, 9, 11, 13, 15, 18, and 20 of pregnancy as well as 3 days postpartum. Relative expression levels of Pcsk1, Pcsk2, Furin, Pcsk4, Pcsk5, Pcsk6, Pcsk7, Mbtps1 and Pcsk9 were determined with real-time PCR. Results were reported as fold-change over the level at Day 0 of pregnancy. Results Results showed that Pcsk1 and Pcsk6 were upregulated as gestation advanced, in parallel with an observed increase in relaxin transcript. Pcsk2 showed downregulation as gestation advanced, while Pcsk5 showed relatively higher levels in early pregnancy and postpartum, but lower level in mid-pregnancy. On the other hand, Furin, Pcsk4, Pcsk7, Mbtps1 and Pcsk9 showed little change of expression throughout gestation. Conclusion PC1/3 (PCSK1) and PACE4 (PCSK6) may play an important role in proprotein processing in the ovary during late pregnancy.
Collapse
Affiliation(s)
- Simon Cm Kwok
- ORTD, Albert Einstein Medical Center, 5501 Old York Road, Philadelphia, PA 19141-3098, USA.
| | | | | | | |
Collapse
|
140
|
Kalhan A, Rees A. A potential role for monoclonal antibodies in clinical lipidology: can we look beyond statins? Curr Opin Lipidol 2013; 24:457-8. [PMID: 24005222 DOI: 10.1097/mol.0b013e3283654f27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
141
|
Essalmani R, Susan-Resiga D, Chamberland A, Asselin MC, Canuel M, Constam D, Creemers JW, Day R, Gauthier D, Prat A, Seidah NG. Furin is the primary in vivo convertase of angiopoietin-like 3 and endothelial lipase in hepatocytes. J Biol Chem 2013; 288:26410-8. [PMID: 23918928 DOI: 10.1074/jbc.m113.501304] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The proprotein convertases (PCs) furin, PC5/6, and PACE4 exhibit unique and/or complementary functions. Their knock-out (KO) in mice resulted in strong and specific phenotypes demonstrating that, in vivo, these PCs are unique and essential during development. However, they also exhibit redundant functions. Liver angiopoietin-like 3 (ANGPTL3) inhibits lipolysis by binding to lipoprotein lipases. It is found in the plasma as full length and truncated forms. The latter is more active and generated by cleavage at a furin-like site. Endothelial lipase (EL) binds heparin sulfate proteoglycans on cell surfaces and catalyzes the hydrolysis of HDL phospholipids. EL activity is regulated by two endogenous inhibitors, ANGPTL3 and ANGPTL4, and by PCs that inactivate EL through cleavage releasing the N-terminal catalytic and C-terminal lipid-binding domains. Herein, because furin and PC5/6 complete KOs are lethal, we used mice lacking furin or PC5/6 specifically in hepatocytes (hKO) or mice completely lacking PACE4. In primary hepatocytes, ANGPTL3 was processed into a shorter form of ANGPTL3 intracellularly by furin only, and extracellularly mainly by PACE4. In vivo, the absence of furin in hepatocytes reduced by ∼50% the circulating levels of cleaved ANGPTL3, while the lack of PACE4 had only a minor effect. Analysis of the EL processing in primary hepatocytes and in vivo revealed that it is mostly cleaved by furin. However, the lack of furin or PC5/6 in hepatocytes and complete PACE4 KO did not appreciably modify plasma HDL levels or EL activity. Thus, inhibition of furin in liver would not be expected to modify the plasma lipid profiles.
Collapse
|