1
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Geng S, Zhang Y, Lu R, Irimia D, Li L. Resolving neutrophils through genetic deletion of TRAM attenuate atherosclerosis pathogenesis. iScience 2024; 27:110097. [PMID: 38883832 PMCID: PMC11179630 DOI: 10.1016/j.isci.2024.110097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 04/23/2024] [Accepted: 05/21/2024] [Indexed: 06/18/2024] Open
Abstract
Systemic neutrophil dysregulation contributes to atherosclerosis pathogenesis, and restoring neutrophil homeostasis may be beneficial for treating atherosclerosis. Herein, we report that a homeostatic resolving subset of neutrophils exists in mice and humans characterized by the low expression of TRAM, correlated with reduced expression of inflammatory mediators (leukotriene B4 [LTB4] and elastase) and elevated expression of anti-inflammatory resolving mediators (resolvin D1 [RvD1] and CD200R). TRAM-deficient neutrophils can potently improve vascular integrity and suppress atherosclerosis pathogenesis when adoptively transfused into recipient atherosclerotic animals. Mechanistically, we show that TRAM deficiency correlates with reduced expression of 5-lipoxygenase (LOX5) activating protein (LOX5AP), dislodges nuclear localization of LOX5, and switches the lipid mediator secretion from pro-inflammatory LTB4 to pro-resolving RvD1. TRAM also serves as a stress sensor of oxidized low-density lipoprotein (oxLDL) and/or free cholesterol and triggers inflammatory signaling processes that facilitate elastase release. Together, our study defines a unique neutrophil population characterized by reduced TRAM, capable of homeostatic resolution and treatment of atherosclerosis.
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Affiliation(s)
- Shuo Geng
- Department of Biological Sciences, Virginia Tech, Blacksburg VA 24061, USA
| | - Yao Zhang
- Department of Biological Sciences, Virginia Tech, Blacksburg VA 24061, USA
| | - Ran Lu
- Department of Biological Sciences, Virginia Tech, Blacksburg VA 24061, USA
| | - Daniel Irimia
- Center for Engineering in Medicine & Surgery, Massachusetts General Hospital, Harvard Medical School, Shriners Burns Hospital, Boston, MA 02114, USA
| | - Liwu Li
- Department of Biological Sciences, Virginia Tech, Blacksburg VA 24061, USA
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2
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Cheng Y, Chen Y, Li K, Liu S, Pang C, Gao L, Xie J, Wenjing LV, Yu H, Deng B. How inflammation dictates diabetic peripheral neuropathy: An enlightening review. CNS Neurosci Ther 2024; 30:e14477. [PMID: 37795833 PMCID: PMC11017439 DOI: 10.1111/cns.14477] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/28/2023] [Accepted: 09/08/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND Diabetic peripheral neuropathy (DPN) constitutes a debilitating complication associated with diabetes. Although, the past decade has seen rapid developments in understanding the complex etiology of DPN, there are no approved therapies that can halt the development of DPN, or target the damaged nerve. Therefore, clarifying the pathogenesis of DPN and finding effective treatment are the crucial issues for the clinical management of DPN. AIMS This review is aiming to summary the current knowledge on the pathogenesis of DPN, especially the mechanism and application of inflammatory response. METHODS We systematically summarized the latest studies on the pathogenesis and therapeutic strategies of diabetic neuropathy in PubMed. RESULTS In this seminal review, the underappreciated role of immune activation in the progression of DPN is scrutinized. Novel insights into the inflammatory regulatory mechanisms of DPN have been unearthed, illuminating potential therapeutic strategies of notable clinical significance. Additionally, a nuanced examination of DPN's complex etiology, including aberrations in glycemic control and insulin signaling pathways, is presented. Crucially, an emphasis has been placed on translating these novel understandings into tangible clinical interventions to ameliorate patient outcomes. CONCLUSIONS This review is distinguished by synthesizing cutting-edge mechanisms linking inflammation to DPN and identifying innovative, inflammation-targeted therapeutic approaches.
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Affiliation(s)
- Yifan Cheng
- Center for Rehabilitation Medicine, Department of Neurology, Zhejiang Provincial People's HospitalAffiliated People's Hospital, Hangzhou Medical CollegeHangzhouChina
| | - Yinuo Chen
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
- First School of Clinical MedicineWenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Kezheng Li
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
- First School of Clinical MedicineWenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Shuwei Liu
- First School of Clinical MedicineWenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Chunyang Pang
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Lingfei Gao
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
| | - Jiali Xie
- Department of Neurology, Shanghai East HospitalTongji UniversityShanghaiP.R. China
| | - L. V. Wenjing
- Department of GeriatricsThe Affiliated Hospital of Qingdao UniversityQingdaoShandong ProvinceChina
| | - Huan Yu
- Department of PediatricsSecond Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Binbin Deng
- Department of NeurologyFirst Affiliated Hospital of Wenzhou Medical UniversityWenzhouZhejiang ProvinceChina
- First School of Clinical MedicineWenzhou Medical UniversityWenzhouZhejiang ProvinceChina
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3
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Nihei W, Kato A, Himeno T, Kondo M, Nakamura J, Kamiya H, Sango K, Kato K. Hyperglycaemia Aggravates Oxidised Low-Density Lipoprotein-Induced Schwann Cell Death via Hyperactivation of Toll-like Receptor 4. Neurol Int 2024; 16:370-379. [PMID: 38525707 PMCID: PMC10961767 DOI: 10.3390/neurolint16020027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 03/26/2024] Open
Abstract
Increased low-density lipoprotein levels are risk factors for diabetic neuropathy. Diabetes mellitus is associated with elevated metabolic stress, leading to oxidised low-density lipoprotein formation. Therefore, it is important to investigate the mechanisms underlying the pathogenesis of diabetic neuropathy in diabetes complicated by dyslipidaemia with increased levels of oxidised low-density lipoprotein. Here, we examined the effects of hyperglycaemia and oxidised low-density lipoprotein treatment on Schwann cell death and its underlying mechanisms. Immortalised mouse Schwann cells were treated with oxidised low-density lipoprotein under normo- or hyperglycaemic conditions. We observed that oxidised low-density lipoprotein-induced cell death increased under hyperglycaemic conditions compared with normoglycaemic conditions. Moreover, hyperglycaemia and oxidised low-density lipoprotein treatment synergistically upregulated the gene and protein expression of toll-like receptor 4. Pre-treatment with TAK-242, a selective toll-like receptor 4 signalling inhibitor, attenuated hyperglycaemia- and oxidised low-density lipoprotein-induced cell death and apoptotic caspase-3 pathway. Our findings suggest that the hyperactivation of toll-like receptor 4 signalling by hyperglycaemia and elevated oxidised low-density lipoprotein levels synergistically exacerbated diabetic neuropathy; thus, it can be a potential therapeutic target for diabetic neuropathy.
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Affiliation(s)
- Wataru Nihei
- Laboratory of Medicine, Aichi Gakuin University School of Pharmacy, Nagoya 464-8650, Japan; (W.N.); (A.K.)
| | - Ayako Kato
- Laboratory of Medicine, Aichi Gakuin University School of Pharmacy, Nagoya 464-8650, Japan; (W.N.); (A.K.)
| | - Tatsuhito Himeno
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1195, Japan (M.K.); (H.K.)
| | - Masaki Kondo
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1195, Japan (M.K.); (H.K.)
| | - Jiro Nakamura
- Department of Innovative Diabetes Therapy, Aichi Medical University School of Medicine, Nagakute 480-1195, Japan;
| | - Hideki Kamiya
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1195, Japan (M.K.); (H.K.)
| | - Kazunori Sango
- Diabetic Neuropathy Project, Department of Diseases and Infection, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan;
| | - Koichi Kato
- Laboratory of Medicine, Aichi Gakuin University School of Pharmacy, Nagoya 464-8650, Japan; (W.N.); (A.K.)
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4
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Sloan G, Selvarajah D, Tesfaye S. Pathogenesis, diagnosis and clinical management of diabetic sensorimotor peripheral neuropathy. Nat Rev Endocrinol 2021; 17:400-420. [PMID: 34050323 DOI: 10.1038/s41574-021-00496-z] [Citation(s) in RCA: 158] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/15/2021] [Indexed: 02/08/2023]
Abstract
Diabetic sensorimotor peripheral neuropathy (DSPN) is a serious complication of diabetes mellitus and is associated with increased mortality, lower-limb amputations and distressing painful neuropathic symptoms (painful DSPN). Our understanding of the pathophysiology of the disease has largely been derived from animal models, which have identified key potential mechanisms. However, effective therapies in preclinical models have not translated into clinical trials and we have no universally accepted disease-modifying treatments. Moreover, the condition is generally diagnosed late when irreversible nerve damage has already taken place. Innovative point-of-care devices have great potential to enable the early diagnosis of DSPN when the condition might be more amenable to treatment. The management of painful DSPN remains less than optimal; however, studies suggest that a mechanism-based approach might offer an enhanced benefit in certain pain phenotypes. The management of patients with DSPN involves the control of individualized cardiometabolic targets, a multidisciplinary approach aimed at the prevention and management of foot complications, and the timely diagnosis and management of neuropathic pain. Here, we discuss the latest advances in the mechanisms of DSPN and painful DSPN, originating both from the periphery and the central nervous system, as well as the emerging diagnostics and treatments.
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Affiliation(s)
- Gordon Sloan
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Dinesh Selvarajah
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
- Department of Oncology and Human Metabolism, University of Sheffield, Sheffield, UK
| | - Solomon Tesfaye
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK.
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5
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Stino AM, Rumora AE, Kim B, Feldman EL. Evolving concepts on the role of dyslipidemia, bioenergetics, and inflammation in the pathogenesis and treatment of diabetic peripheral neuropathy. J Peripher Nerv Syst 2021; 25:76-84. [PMID: 32412144 DOI: 10.1111/jns.12387] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/11/2020] [Accepted: 05/11/2020] [Indexed: 12/14/2022]
Abstract
Diabetic peripheral neuropathy (DPN) is one of the most widespread and disabling neurological conditions, accounting for half of all neuropathy cases worldwide. Despite its high prevalence, no approved disease modifying therapies exist. There is now a growing body of evidence that DPN secondary to type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) represents different disease processes, with T2DM DPN best understood within the context of metabolic syndrome rather than hyperglycemia. In this review, we highlight currently understood mechanisms of DPN, along with their corresponding potential therapeutic targets. We frame this discussion within a practical overview of how the field evolved from initial human observations to murine pathomechanistic and therapeutic models into ongoing and human clinical trials, with particular emphasis on T2DM DPN and metabolic syndrome.
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Affiliation(s)
- Amro M Stino
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA.,Division of Neuromuscular Medicine, Ann Arbor, Michigan, USA
| | - Amy E Rumora
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
| | - Bhumsoo Kim
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
| | - Eva L Feldman
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, Michigan, USA.,Division of Neuromuscular Medicine, Ann Arbor, Michigan, USA
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6
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Pergolizzi JV, Magnusson P, LeQuang JA, Razmi R, Zampogna G, Taylor R. Statins and Neuropathic Pain: A Narrative Review. Pain Ther 2020; 9:97-111. [PMID: 32020545 PMCID: PMC7203325 DOI: 10.1007/s40122-020-00153-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Indexed: 12/11/2022] Open
Abstract
The frequently prescribed drug class of statins have pleiotropic effects and have been implicated in neuropathic pain syndromes. This narrative review examines studies of statin-induced neuropathic pain which to date have been conducted only in animal models. However, the pathophysiology of diabetic neuropathy in humans may shed some light on the etiology of neuropathic pain. Statins have exhibited a paradoxical effect in that statins appear to reduce neuropathic pain in animals but have been associated with neuropathic pain in humans. While there are certain postulated mechanisms offering elucidation as to how statins might be associated with neuropathic pain, there is, as the American Heart Association stated, to date no definitive association between statins and neuropathic pain. Statins are important drugs that reduce cardiovascular risk factors and should be prescribed to appropriate patients with these risk factors but some of this population is also at elevated risk for neuropathic pain from other causes.
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Affiliation(s)
| | - Peter Magnusson
- Cardiology Research Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
- Centre for Research and Development, Region Gävleborg/Uppsala University, Gävle, Sweden
| | | | - Robin Razmi
- Department of Infectious Disease, Region Gävleborg/Uppsala University, Gävle, Sweden
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7
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Abstract
The global epidemic of prediabetes and diabetes has led to a corresponding epidemic of complications of these disorders. The most prevalent complication is neuropathy, of which distal symmetric polyneuropathy (for the purpose of this Primer, referred to as diabetic neuropathy) is very common. Diabetic neuropathy is a loss of sensory function beginning distally in the lower extremities that is also characterized by pain and substantial morbidity. Over time, at least 50% of individuals with diabetes develop diabetic neuropathy. Glucose control effectively halts the progression of diabetic neuropathy in patients with type 1 diabetes mellitus, but the effects are more modest in those with type 2 diabetes mellitus. These findings have led to new efforts to understand the aetiology of diabetic neuropathy, along with new 2017 recommendations on approaches to prevent and treat this disorder that are specific for each type of diabetes. In parallel, new guidelines for the treatment of painful diabetic neuropathy using distinct classes of drugs, with an emphasis on avoiding opioid use, have been issued. Although our understanding of the complexities of diabetic neuropathy has substantially evolved over the past decade, the distinct mechanisms underlying neuropathy in type 1 and type 2 diabetes remains unknown. Future discoveries on disease pathogenesis will be crucial to successfully address all aspects of diabetic neuropathy, from prevention to treatment.
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8
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Feldman EL, Callaghan BC, Pop-Busui R, Zochodne DW, Wright DE, Bennett DL, Bril V, Russell JW, Viswanathan V. Diabetic neuropathy. Nat Rev Dis Primers 2019; 5:42. [PMID: 31197183 PMCID: PMC7096070 DOI: 10.1038/s41572-019-0097-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The global epidemic of prediabetes and diabetes has led to a corresponding epidemic of complications of these disorders. The most prevalent complication is neuropathy, of which distal symmetric polyneuropathy (for the purpose of this Primer, referred to as diabetic neuropathy) is very common. Diabetic neuropathy is a loss of sensory function beginning distally in the lower extremities that is also characterized by pain and substantial morbidity. Over time, at least 50% of individuals with diabetes develop diabetic neuropathy. Glucose control effectively halts the progression of diabetic neuropathy in patients with type 1 diabetes mellitus, but the effects are more modest in those with type 2 diabetes mellitus. These findings have led to new efforts to understand the aetiology of diabetic neuropathy, along with new 2017 recommendations on approaches to prevent and treat this disorder that are specific for each type of diabetes. In parallel, new guidelines for the treatment of painful diabetic neuropathy using distinct classes of drugs, with an emphasis on avoiding opioid use, have been issued. Although our understanding of the complexities of diabetic neuropathy has substantially evolved over the past decade, the distinct mechanisms underlying neuropathy in type 1 and type 2 diabetes remains unknown. Future discoveries on disease pathogenesis will be crucial to successfully address all aspects of diabetic neuropathy, from prevention to treatment.
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Affiliation(s)
- Eva L. Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.,
| | | | - Rodica Pop-Busui
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes (MEND), University of Michigan, Ann Arbor, MI, USA
| | - Douglas W. Zochodne
- Division of Neurology, Department of Medicine and the Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Douglas E. Wright
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - David L. Bennett
- Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, UK
| | - Vera Bril
- Division of Neurology, Department of Medicine, University of Toronto and University Health Network, Toronto, Ontario, Canada.,Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - James W. Russell
- Department of Neurology, University of Maryland and VA Maryland Health Care System, Baltimore, MD, USA
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9
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Hinder LM, Murdock BJ, Park M, Bender DE, O'Brien PD, Rumora AE, Hur J, Feldman EL. Transcriptional networks of progressive diabetic peripheral neuropathy in the db/db mouse model of type 2 diabetes: An inflammatory story. Exp Neurol 2018; 305:33-43. [PMID: 29550371 DOI: 10.1016/j.expneurol.2018.03.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/14/2018] [Accepted: 03/13/2018] [Indexed: 12/13/2022]
Abstract
Diabetic peripheral neuropathy is the most common complication of diabetes and a source of considerable morbidity. Numerous molecular pathways are linked to neuropathic progression, but it is unclear whether these pathways are altered throughout the course of disease. Moreover, the methods by which these molecular pathways are analyzed can produce significantly different results; as such it is often unclear whether previously published pathways are viable targets for novel therapeutic approaches. In the current study we examine changes in gene expression patterns in the sciatic nerve (SCN) and dorsal root ganglia (DRG) of db/db diabetic mice at 8, 16, and 24 weeks of age using microarray analysis. Following the collection and verification of gene expression data, we utilized both self-organizing map (SOM) analysis and differentially expressed gene (DEG) analysis to detect pathways that were altered at all time points. Though there was some variability between SOM and DEG analyses, we consistently detected altered immune pathways in both the SCN and DRG over the course of disease. To support these results, we further used multiplex analysis to assess protein changes in the SCN of diabetic mice; we found that multiple immune molecules were upregulated at both early and later stages of disease. In particular, we found that matrix metalloproteinase-12 was highly upregulated in microarray and multiplex data sets suggesting it may play a role in disease progression.
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Affiliation(s)
- Lucy M Hinder
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Benjamin J Murdock
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Meeyoung Park
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Diane E Bender
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Phillipe D O'Brien
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Amy E Rumora
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Junguk Hur
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203-9037, USA
| | - Eva L Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA.
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10
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Ratheesh M, Svenia JP, Asha S, Sandya S, Girishkumar B, Krishnakumar IM. Anti-inflammatory effect of a novel formulation of coconut inflorescence sap against ox-LDL induced inflammatory responses in human peripheral blood mononuclear cells by modulating TLR-NF-κB signaling pathway. Toxicol Mech Methods 2017. [DOI: 10.1080/15376516.2017.1344339] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- M. Ratheesh
- Department of Biochemistry, St. Thomas College, Pala, India
| | - Jose P. Svenia
- Department of Biochemistry, St. Thomas College, Pala, India
| | - S. Asha
- Department of Biochemistry, St. Thomas College, Pala, India
| | - S. Sandya
- Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India
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11
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Yamchuen P, Jeenapongsa R, Nudmamud-Thanoi S, Limpeanchob N. Low density lipoprotein increases amyloid precursor protein processing to amyloidogenic pathway in differentiated SH-SY5Y cells. Biologia (Bratisl) 2017. [DOI: 10.1515/biolog-2017-0024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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12
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Wang X, Sun Y, Yang H, Lu Y, Li L. Oxidized Low-Density Lipoprotein Induces Apoptosis in Cultured Neonatal Rat Cardiomyocytes by Modulating the TLR4/NF-κB Pathway. Sci Rep 2016; 6:27866. [PMID: 27279424 PMCID: PMC4899754 DOI: 10.1038/srep27866] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/26/2016] [Indexed: 12/14/2022] Open
Abstract
This study was designed to investigate the apoptosis induced by oxidized low-density lipoprotein (ox-LDL) in cultured neonatal rat cardiomyocytes and explore the possible mechanisms. We evaluated whether ox-LDL-induced apoptosis depended in part on the activation of toll-like receptor-4(TLR4)/Nuclear factor κB (NF-κB) signaling pathway. Cells were cultivated with and without ox-LDL. Cell apoptosis was evaluated by flow cytometry. Immunofluorescence, western blot analysis and quantitative real-time polymerase chain reaction (qRT-PCR) were conducted to assess protein or mRNA expressions. Resatorvid (TAK-242), an exogenous synthetic antagonist for TLR4, was used to inhibit TLR4 signal transduction. Dose- and time-dependent apoptotic index of cardiomyocytes occurred after ox-LDL treatment. Incubation of cardiomyocytes with ox-LDL (50 μg/mL) for 24 hours increased TLR4 and NF-κB expressions significantly. Decrease of Bcl-2/Bax protein ratio, activation of caspase-3 and 9 were also detected. Ox-LDL-induced cardiomyocyte apoptosis, TLR4 and NF-κB expressions were attenuated by pretreatment with TAK-242. In conclusion, our findings indicate that the apoptosis induced by ox-LDL in cultured neonatal rat cardiomyocytes at least in part by modulating the TLR4/NF-κB signaling pathway.
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Affiliation(s)
- Xiantao Wang
- Department of Cardiology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Yuhan Sun
- Department of Cardiology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Huafeng Yang
- Department of Cardiology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Yuanxi Lu
- Department of Cardiology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
| | - Lang Li
- Department of Cardiology, the First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China
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13
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Yan H, Li Y, Peng X, Huang D, Gui L, Huang B. Resistance of mitochondrial DNA-depleted cells against oxidized low-density lipoprotein-induced macrophage pyroptosis. Mol Med Rep 2016; 13:4393-9. [PMID: 27035880 DOI: 10.3892/mmr.2016.5077] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 02/08/2016] [Indexed: 11/05/2022] Open
Abstract
Oxidized low-density lipoprotein (Ox-LDL)-induced macrophage pyroptosis is critical in atherosclerosis inflammation and plaque instability. It has been reported that mitochondrial (mt)DNA-depleted (rho0) cells demonstrate resistance to apoptosis. However, little is known about the susceptibility of rho0 cells to Ox-LDL-induced macrophage pyroptosis. Pyroptosis, a caspase-1-dependent programmed cell death, which compromises membrane integrity, cleaves pro-interleukin (IL)‑1β and pro‑IL‑18 into IL‑1β and IL‑18, respectively and releases damage‑associated molecular pattern molecules, is triggered by a variety of stimuli, including Ox‑LDL. In the present study, the expression levels of cleaved caspase‑1 and IL‑1β in Ox‑LDL‑treated J774A.1 rho0 cells were observed to be significantly decreased when compared with Ox‑LDL‑treated J774A.1 normal cells. Furthermore, J774A.1 rho0 cells exhibited a significant reduction in the ratios of dead cells and lactate dehydrogenase release following Ox‑LDL stimulation compared with the J774A.1 normal cells. In addition, the loss of mtDNA did not influence Ox‑LDL‑induced cholesterol accumulation in J774A.1 rho0 cells, which was observed by Oil Red O staining and CHOD‑PAP assay. Finally, J774A.1 rho0 cells exhibited reduced reactive oxygen species (ROS) production and were capable of maintaining the mitochondrial membrane potential following Ox‑LDL treatment. Thus, the results indicate that the loss of mtDNA potentially rendered murine macrophage J774A.1 resistant to Ox‑LDL‑induced pyroptosis by mitigating NACHT, LRR and PYD domains-containing protein 3 inflammasome activation through reducing ROS production. In addition, mtDNA depletion did not interrupt Ox-LDL-induced intracellular lipid accumulation and continued to maintain the mitochondrial membrane potential.
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Affiliation(s)
- Hai Yan
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Yunyun Li
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Xue Peng
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Dake Huang
- Comprehensive Laboratory, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Li Gui
- Comprehensive Laboratory, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Baojun Huang
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, P.R. China
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14
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Wu S, Cao X, He R, Xiong K. Detrimental impact of hyperlipidemia on the peripheral nervous system: A novel target of medical epidemiological and fundamental research study. Neural Regen Res 2015; 7:392-9. [PMID: 25774180 PMCID: PMC4350124 DOI: 10.3969/j.issn.1673-5374.2012.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 12/14/2011] [Indexed: 01/07/2023] Open
Abstract
Recently, epidemiological studies on the etiology of peripheral neuropathies have revealed that hyperlipidemia is a novel risk factor. Plasma lipid levels were confirmed to be associated with the incidence of many peripheral neuropathies including axonal distal polyneuropathy, vision and hearing loss, motor nerve system lesions and sympathetic nerve system dysfunction. Moreover, different lipid components such as cholesterol, triacylglycerols and lipoprotein are involved in the pathogenesis of these neuropathies. This review aimed to discuss the effect of hyperlipidemia on the peripheral nervous system and its association with peripheral neuropathies. Furthermore, a detailed discussion focusing on the explicit mechanisms related to hyperlipidemia-induced peripheral neuropathies is presented here. These mechanisms, including intracellular oxidative stress, inflammatory lesions, ischemia and dysregulation of local lipid metabolism, share pathways and interact mutually. In addition, we examined current information on clinical trials to prevent and treat peripheral neuropathies caused by hyperlipidemia, with a predictive discussion regarding the orientation of future investigations.
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Affiliation(s)
- Song Wu
- Department of Orthopedics, Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, China
| | - Xu Cao
- Clinical Medicine Eight-year Program, 01 Class, 07 Grade, Central South University, Changsha 410013, Hunan Province, China
| | - Rongzhen He
- Department of Orthopedics, Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, China
| | - Kun Xiong
- Department of Anatomy and Neurobiology, Xiangya Medical School of Central South University, Changsha 410013, Hunan Province, China
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15
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Yamchuen P, Aimjongjun S, Limpeanchob N. Oxidized low density lipoprotein increases acetylcholinesterase activity correlating with reactive oxygen species production. Neurochem Int 2014; 78:1-6. [DOI: 10.1016/j.neuint.2014.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 06/30/2014] [Accepted: 07/24/2014] [Indexed: 01/08/2023]
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16
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Mao X, Xie L, Greenberg DA. LOX-1 expression and oxidized LDL uptake and toxicity in the HN33 neuronal cell line. Neurosci Lett 2014; 580:182-5. [DOI: 10.1016/j.neulet.2014.03.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 03/24/2014] [Accepted: 03/26/2014] [Indexed: 12/28/2022]
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Tse KH, Chow KBS, Leung WK, Wong YH, Wise H. Primary sensory neurons regulate Toll-like receptor-4-dependent activity of glial cells in dorsal root ganglia. Neuroscience 2014; 279:10-22. [PMID: 25171787 DOI: 10.1016/j.neuroscience.2014.08.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/10/2014] [Accepted: 08/11/2014] [Indexed: 12/21/2022]
Abstract
Toll-like receptor-4 (TLR4) has been identified in primary sensory neurons, both in vivo and in vitro, but is reportedly absent from satellite glial cells (SGCs). Herein we reveal that, in rat dorsal root ganglia (DRG), SGCs do express TLR4 but this expression is inhibited by direct contact with neurons. Thus, TLR4 mRNA and protein is strongly up-regulated in isolated DRG glial cells in the absence of neurons. Lipopolysaccharide (LPS) increased cyclooxygenase-2 (COX-2) and tumor necrosis factor-α (TNFα) mRNA expression with greater efficacy in DRG glial cell cultures than in mixed DRG cell cultures containing TLR4-positive neurons. Using an insert co-culture system, we have shown that neuronal inhibition of glial cell TLR4 is likely to be dependent on cell-cell contact rather than diffusible factors from neurons. LPS stimulated prostaglandin E2 (PGE2) production from DRG glial cells in a TLR4- and COX-2-dependent manner. In addition, exogenous PGE2 potentiated LPS-stimulated COX-2 mRNA while inhibiting TNFα mRNA expression by DRG cells, suggestive of a complex regulatory system to control inflammation within the DRG. In addition to LPS, conditioned medium from heat-shocked DRG neurons also increased COX-2 mRNA expression in DRG glial cells in a partially TLR4-dependent manner. We therefore hypothesize that neuronal suppression of glial TLR4 activity is a protective mechanism to prevent uncontrolled inflammation within the DRG. Under conditions where DRG neuronal viability is compromised, DRG glial cells become responsive to PAMPs (pathogen-associated molecular patterns) and DAMPs (danger-associated molecular patterns) and generate a range of classical inflammatory responses.
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Affiliation(s)
- K-H Tse
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - K B S Chow
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - W K Leung
- Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Y H Wong
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong Special Administrative Region
| | - H Wise
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
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18
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Zeng Q, Song R, Ao L, Xu D, Venardos N, Fullerton DA, Meng X. Augmented osteogenic responses in human aortic valve cells exposed to oxLDL and TLR4 agonist: a mechanistic role of Notch1 and NF-κB interaction. PLoS One 2014; 9:e95400. [PMID: 24810405 PMCID: PMC4014478 DOI: 10.1371/journal.pone.0095400] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 03/24/2014] [Indexed: 11/18/2022] Open
Abstract
Aortic valve calcification causes the progression of calcific aortic valve disease (CAVD). Stimulation of aortic valve interstitial cells (AVICs) with lipopolysaccharide (LPS) up-regulates the expression of osteogenic mediators, and NF-κB plays a central role in mediating AVIC osteogenic responses to Toll-like receptor 4 (TLR4) stimulation. Diseased aortic valves exhibit greater levels of oxidized low-density lipoprotein (oxLDL). This study tested the hypothesis that oxLDL augments the osteogenic responses in human AVICs through modulation of NF-κB and Notch1 activation. AVICs isolated from normal human aortic valves were treated with LPS (0.1 µg/ml), oxLDL (20 µg/ml) or LPS plus oxLDL for 48 h. OxLDL alone increased cellular bone morphogenetic protein-2 (BMP-2) levels while it had no effect on alkaline phosphatase (ALP) levels. Cells exposed to LPS plus oxLDL produced higher levels of BMP-2 and ALP than cells exposed to LPS alone. Further, LPS plus oxLDL induced greater NF-κB activation, and inhibition of NF-κB markedly reduced the expression of BMP-2 and ALP in cells treated with LPS plus oxLDL. OxLDL also induced Notch1 activation and resulted in augmented Notch1 activation when it was combined with LPS. Inhibition of Notch1 cleavage attenuated NF-κB activation induced by LPS plus oxLDL, and inhibition of NF-κB suppressed the expression of BMP-2 and ALP induced by the synergistic effect of Jagged1 and LPS. These findings demonstrate that oxLDL up-regulates BMP-2 expression in human AVICs and synergizes with LPS to elicit augmented AVIC osteogenic responses. OxLDL exerts its effect through modulation of the Notch1-NF-κB signaling cascade. Thus, oxLDL may play a role in the mechanism underlying CAVD progression.
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Affiliation(s)
- Qingchun Zeng
- Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Rui Song
- Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Pathophysiology, Southern Medical University, Guangzhou, Guangdong, China
| | - Lihua Ao
- Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Dingli Xu
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Neil Venardos
- Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America
| | - David A. Fullerton
- Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Xianzhong Meng
- Department of Surgery, University of Colorado Denver, Aurora, Colorado, United States of America
- * E-mail:
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Lipopolysaccharide differentially modulates expression of cytokines and cyclooxygenases in dorsal root ganglion cells via Toll-like receptor-4 dependent pathways. Neuroscience 2014; 267:241-51. [DOI: 10.1016/j.neuroscience.2014.02.041] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 11/19/2022]
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20
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Ustinova EE, Shurin GV, Gutkin DW, Shurin MR. The role of TLR4 in the paclitaxel effects on neuronal growth in vitro. PLoS One 2013; 8:e56886. [PMID: 23441224 PMCID: PMC3575491 DOI: 10.1371/journal.pone.0056886] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 01/17/2013] [Indexed: 12/19/2022] Open
Abstract
Paclitaxel (Pac) is an antitumor agent that is widely used for treatment of solid cancers. While being effective as a chemotherapeutic agent, Pac in high doses is neurotoxic, specifically targeting sensory innervations. In view of these toxic effects associated with conventional chemotherapy, decreasing the dose of Pac has been recently suggested as an alternative approach, which might limit neurotoxicity and immunosuppression. However, it remains unclear if low doses of Pac retain its neurotoxic properties or might exhibit unusual effects on neuronal cells. The goal of this study was to analyze the concentration-dependent effect of Pac on isolated and cultured DRG neuronal cells from wild-type and TLR4 knockout mice. Three different morphological parameters were analyzed: the number of neurons which developed neurites, the number of neurites per cell and the total length of neurites per cell. Our data demonstrate that low concentrations of Pac (0.1 nM and 0.5 nM) do not influence the neuronal growth in cultures in both wild type and TLR4 knockout mice. Higher concentrations of Pac (1–100 nM) had a significant effect on DRG neurons from wild type mice, affecting the number of neurons which developed neurites, number of neurites per cell, and the length of neurites. In DRG from TLR4 knockout mice high concentrations of Pac showed a similar effect on the number of neurons which developed neurites and the length of neurites. At the same time, the number of neurites per cell, indicating the process of growth cone initiation, was not affected by high concentrations of Pac. Thus, our data showed that Pac in high concentrations has a significant damaging effect on axonal growth and that this effect is partially mediated through TLR4 pathways. Low doses of Pac are devoid of neuronal toxicity and thus can be safely used in a chemomodulation mode.
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Affiliation(s)
- Elena E Ustinova
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America.
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21
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Zhang Z, Zhang M, Li Y, Liu S, Ping S, Wang J, Ning F, Xie F, Li C. Simvastatin inhibits the additive activation of ERK1/2 and proliferation of rat vascular smooth muscle cells induced by combined mechanical stress and oxLDL through LOX-1 pathway. Cell Signal 2012; 25:332-40. [PMID: 23072789 DOI: 10.1016/j.cellsig.2012.10.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 10/10/2012] [Indexed: 01/11/2023]
Abstract
Vein grafts interposed into arteries are susceptible to the development of atherosclerosis due to rapid increases in blood pressure. This process is accelerated in patients with hyperlipidemia. The molecular mechanism underlying this process is unknown. In this study, quiescent rat vascular smooth muscle cells (VSMCs) were treated in vitro with mechanical stretch stress (10% elongation) with and without oxLDL (25 μg/ml) in the presence and absence of simvastatin (2.5 μmol/L). The results demonstrate that stretch stress and oxLDL can each induce activation of ERK1/2 and Ki-67 expression in VSMCs, but the peak levels of ERK activation and Ki-67 expression were observed in groups subjected to both stretch stress and oxLDL. Simvastatin was found to inhibit increased ERK activation and Ki-67 expression in VSMCs subjected to stretch stress with or without oxLDL. Mechanically, simvastatin was also found to inhibit increased expression of LOX-1 (a receptor of oxLDL) in VSMCs subjected to stretch stress with or without oxLDL. Knockdown of LOX-1 via small interfering RNAs (siRNA-LOX-1) resulted in obvious inhibition of ERK activation in VSMCs subjected to stretch stress with and without oxLDL. These results suggest that combined stretch stress and oxLDL can additively promote the activation of ERK1/2 leading to accelerated proliferation of VSMCs (e.g. increased Ki-67 expression) via LOX-1 signal pathway. This was found to be partially inhibited by simvastatin. These results may provide important data for the treatment and prevention of hypertension with or without hyperlipidemia.
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Affiliation(s)
- Zhengyu Zhang
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
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Singla S, Ding Z, Mehta JL. Arterial wall-axon reflex: a potential player in atherosclerosis. Ther Adv Cardiovasc Dis 2012; 6:181-4. [PMID: 23045192 DOI: 10.1177/1753944712460421] [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: 11/17/2022] Open
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Abstract
Vascular endothelial dysfunction is determined by both genetic and environmental factors that cause decreased bioavailability of the vasodilator nitric oxide. This is a hallmark of atherosclerosis, hypertension, and coronary heart disease, which are major complications of metabolic disorders, including diabetes and obesity. Several therapeutic interventions, including changes in lifestyle as well as pharmacologic treatments, are useful for improving endothelial dysfunction in the face of lipotoxicity. This review discusses the current understanding of molecular and physiologic mechanisms underlying lipotoxicity-mediated endothelial dysfunction as well as relevant therapeutic approaches to ameliorate dyslipidemia and consequent endothelial dysfunction that have the potential to improve cardiovascular and metabolic outcomes.
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Affiliation(s)
- Jeong-a Kim
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, UAB Comprehensive Diabetes Center, University of Alabama at Birmingham, 1808 7th Avenue South, BDB 777, Birmingham, AL 35294-0012, USA
- Department of Cell Biology, University of Alabama at Birmingham, 1808 7th Avenue South, BDB 777, Birmingham, AL 35294, USA
| | - Monica Montagnani
- Department of Biomedical Sciences and Human Oncology, Pharmacology Section, University “Aldo Moro” at Bari, Policlinico, Piazza G. Cesare, 11, 70124 Bari, Italy
| | - Sruti Chandrasekran
- Department of Medicine, Division of Endocrinology, Diabetes & Nutrition, University of Maryland at Baltimore, 660 West Redwood Street, HH 495, Baltimore, MD 21201, USA
| | - Michael J. Quon
- Department of Medicine, Division of Endocrinology, Diabetes & Nutrition, University of Maryland at Baltimore, 660 West Redwood Street, HH 495, Baltimore, MD 21201, USA
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Abstract
Diabetic peripheral neuropathy is a prevalent, disabling disorder. The most common manifestation is distal symmetrical polyneuropathy (DSP), but many patterns of nerve injury can occur. Currently, the only effective treatments are glucose control and pain management. While glucose control substantially decreases the development of neuropathy in those with type 1 diabetes, the effect is probably much smaller in those with type 2 diabetes. Evidence supports the use of specific anticonvulsants and antidepressants for pain management in patients with diabetic peripheral neuropathy. However, the lack of disease-modifying therapies for diabetic DSP makes the identification of new modifiable risk factors essential. Growing evidence supports an association between components of the metabolic syndrome, including prediabetes, and neuropathy. Studies are needed to further explore this association, which has implications for the development of new treatments for this common disorder.
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25
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Pang T, Wang J, Benicky J, Saavedra JM. Minocycline ameliorates LPS-induced inflammation in human monocytes by novel mechanisms including LOX-1, Nur77 and LITAF inhibition. Biochim Biophys Acta Gen Subj 2012; 1820:503-10. [PMID: 22306153 DOI: 10.1016/j.bbagen.2012.01.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 01/13/2012] [Accepted: 01/15/2012] [Indexed: 12/13/2022]
Abstract
BACKGROUND Minocycline exhibits anti-inflammatory properties independent of its antibiotic activity, ameliorating inflammatory responses in monocytes and macrophages. However, the mechanisms of minocycline anti-inflammatory effects are only partially understood. METHODS Human circulating monocytes were cultured in the presence of lipopolysaccharide (LPS), 50 ng/ml, and minocycline (10-40 μM). Gene expression was determined by RT-PCR, cytokine and prostaglandin E(2) (PGE(2)) release by ELISA, protein expression, phosphorylation and nuclear translocation by Western blotting. RESULTS Minocycline significantly reduced the inflammatory response in LPS-challenged monocytes, decreasing LPS-induced transcription of pro-inflammatory tumor-necrosis factor alpha (TNF-α), interleukin-1 beta, interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2), and the LPS-stimulated TNF-α, IL-6 and PGE(2) release. Minocycline inhibited LPS-induced activation of the lectin-like oxidized low density lipoprotein receptor-1 (LOX-1), NF-κB, LPS-induced TNF-α factor (LITAF) and the Nur77 nuclear receptor. Mechanisms involved in the anti-inflammatory effects of minocycline include a reduction of LPS-stimulated p38 mitogen-activated protein kinase (p38 MAPK) activation and stimulation of the phosphoinositide 3-kinase (PI3K)/Akt pathway. CONCLUSIONS We provide novel evidence demonstrating that the anti-inflammatory effects of minocycline in human monocytes include, in addition to decreased NF-κB activation, abrogation of the LPS-stimulated LOX-1, LITAF, Nur77 pathways, p38 MAPK inhibition and PI3K/Akt activation. Our results reveal that minocycline inhibits points of convergence of distinct and interacting signaling pathways mediating multiple inflammatory signals which may influence monocyte activation, traffic and recruitment into the brain. GENERAL SIGNIFICANCE Our results in primary human monocytes contribute to explain the profound anti-inflammatory and protective effects of minocycline in cardiovascular and neurological diseases and may have direct translational relevance.
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Affiliation(s)
- Tao Pang
- Section on Pharmacology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
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26
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Abstract
The renin-angiotensin system (RAS) plays an important role in regulating blood pressure, water-salt balance and the pathogenesis of cardiovascular diseases. Angiotensin II (Ang II) is the physiologically active mediator and mediates the main pathophysiological actions in RAS. Ang II exerts the effects by activating its receptors, primarily type 1 (AT1R) and type 2 (AT2R). Most of the known pathophysiological effects of Ang II are mediated by AT1R activation. The precise physiological function of AT2R is still not clear. Generally, AT2R is considered to oppose the effects of AT1R. Lectin-like oxidized low-density lipoprotein scavenger receptor-1 (LOX-1) is one of the major receptors responsible for binding, internalizing and degrading ox-LDL. The activation of LOX-1 has been known to be related to many pathophysiological events, including endothelial dysfunction and injury, fibroblast growth, and vascular smooth muscle cell hypertrophy. Many of these alterations are present in atherosclerosis, hypertension, and myocardial ischemia and remodeling. A growing body of evidence suggests the existence of a cross-talk between LOX-1 and Ang II receptors. Their interplays are embodied in the reciprocal regulation of their expression and activity. Their interplays are involved in a series of signals. Recent studies suggests that reactive oxygen species (ROS), nitric oxide (NO), protein kinase C (PKC) and mitogen activated protein kinases (MAPKs) are important signals responsible for their cross-talk. This paper reviews these aspects of dyslipidemia and RAS activation.
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Affiliation(s)
- Xianwei Wang
- Division of Cardiology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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27
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Nowicki M, Kosacka J, Serke H, Blüher M, Spanel-Borowski K. Altered sciatic nerve fiber morphology and endoneural microvessels in mouse models relevant for obesity, peripheral diabetic polyneuropathy, and the metabolic syndrome. J Neurosci Res 2011; 90:122-31. [DOI: 10.1002/jnr.22728] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 05/18/2011] [Accepted: 06/08/2011] [Indexed: 02/02/2023]
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Abstract
In patients with diabetes, nerve injury is a common complication that leads to chronic pain, numbness and substantial loss of quality of life. Good glycemic control can decrease the incidence of diabetic neuropathy, but more than half of all patients with diabetes still develop this complication. There is no approved treatment to prevent or halt diabetic neuropathy, and only symptomatic pain therapies, with variable efficacy, are available. New insights into the mechanisms leading to the development of diabetic neuropathy continue to point to systemic and cellular imbalances in metabolites of glucose and lipids. In the PNS, sensory neurons, Schwann cells and the microvascular endothelium are vulnerable to oxidative and inflammatory stress in the presence of these altered metabolic substrates. This Review discusses the emerging cellular mechanisms that are activated in the diabetic milieu of hyperglycemia, dyslipidemia and impaired insulin signaling. We highlight the pathways to cellular injury, thereby identifying promising therapeutic targets, including mitochondrial function and inflammation.
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29
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Su X, Ao L, Shi Y, Johnson TR, Fullerton DA, Meng X. Oxidized low density lipoprotein induces bone morphogenetic protein-2 in coronary artery endothelial cells via Toll-like receptors 2 and 4. J Biol Chem 2011; 286:12213-20. [PMID: 21325271 DOI: 10.1074/jbc.m110.214619] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Vascular calcification is a common complication in atherosclerosis. Bone morphogenetic protein-2 (BMP-2) plays an important role in atherosclerotic vascular calcification. The aim of this study was to determine the effect of oxidized low density lipoprotein (oxLDL) on BMP-2 protein expression in human coronary artery endothelial cells (CAECs), the roles of Toll-like receptor (TLR) 2 and TLR4 in oxLDL-induced BMP-2 expression, and the signaling pathways involved. Human CAECs were stimulated with oxLDL. The roles of TLR2 and TLR4 in oxLDL-induced BMP-2 expression were determined by pretreatment with neutralizing antibody, siRNA, and overexpression. Stimulation with oxLDL increased cellular BMP-2 protein levels in a dose-dependent manner (40-160 μg/ml). Pretreatment with neutralizing antibodies against TLR2 and TLR4 or silencing of these two receptors reduced oxLDL-induced BMP-2 expression. Overexpression of TLR2 and TLR4 enhanced the cellular BMP-2 response to oxLDL. Furthermore, oxLDL was co-localized with TLR2 and TLR4. BMP-2 expression was associated with activation of nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (MAPK), and extracellular signal-regulated kinase (ERK)1/2. Inhibition of NF-κB and ERK1/2 reduced BMP-2 expression whereas inhibition of p38 MAPK had no effect. In conclusion, oxLDL induces BMP-2 expression through TLR2 and TLR4 in human CAECs. The NF-κB and ERK1/2 pathways are involved in the signaling mechanism. These findings underscore an important role for TLR2 and TLR4 in mediating the BMP-2 response to oxLDL in human CAECs and indicate that these two immunoreceptors contribute to the mechanisms underlying atherosclerotic vascular calcification.
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Affiliation(s)
- Xin Su
- Department of Surgery, University of Colorado Denver, Aurora, Colorado 80045, USA
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Thomas LM, Salter RD. Activation of macrophages by P2X7-induced microvesicles from myeloid cells is mediated by phospholipids and is partially dependent on TLR4. THE JOURNAL OF IMMUNOLOGY 2010; 185:3740-9. [PMID: 20709956 DOI: 10.4049/jimmunol.1001231] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
ATP-mediated activation of the purinergic receptor P2X(7) elicits morphological changes and proinflammatory responses in macrophages. These changes include rapid shedding of microvesicles (MV) and the nonconventional secretion of cytokines, such as IL-1beta and IL-18 following priming. In this study, we demonstrate the activation potential of P2X(7)-induced MV isolated from nonprimed murine macrophages. Cotreatment of nonprimed macrophages with ATP and calcium ionophore induced a rapid release of MV that were predominantly 0.5-1 microm in size. Exposure of primary murine bone marrow-derived macrophages to these MV resulted in costimulatory receptor upregulation and TNF-alpha secretion. Cell homogenates or supernatants cleared of MV did not activate macrophages. MV-mediated activation was p38 MAPK and NF-kappaB dependent, and partially dependent on TLR4 activity, but was high-mobility group box 1 independent. Biochemical fractionation of the MV demonstrated that the phospholipid fraction, not the protein fraction, mediated macrophage activation through a TLR4-dependent process. P2X(7) activation is known to induce calcium-independent phospholipase A(2), calcium-dependent phospholipase A(2), and phospholipase D activities, but inhibition of these enzymes did not inhibit MV generation or shedding. However, blocking phospholipase D activity resulted in release of MV incapable of activating recipient macrophages. These data demonstrate a novel mechanism of macrophage activation resulting from exposure to MV from nonprimed macrophages, and identifies phospholipids in these MV as the biologically active component. We suggest that phospholipids delivered by MV may be mediators of sterile inflammation in a number of diseases.
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Affiliation(s)
- L Michael Thomas
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Oxidized low-density lipoprotein (oxLDL) induces cell death in neuroblastoma and survival autophagy in schwannoma cells. Exp Mol Pathol 2010; 89:276-83. [PMID: 20692253 DOI: 10.1016/j.yexmp.2010.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 07/19/2010] [Accepted: 07/30/2010] [Indexed: 11/24/2022]
Abstract
Oxidized low-density lipoprotein (oxLDL) induces apoptosis or autophagy in dependence on the cell type. We here investigated the effect of oxLDL on the B104 neuroblastoma and RN22 schwannoma cells being popular in neuroscience research. Cells were cultivated with and without oxLDL. To generate oxLDL, we added 50 μg/ml nLDL and 50 μM CuSO(4) into the culture medium. After a 24-h-long treatment, oxLDL was detectable in media from both cell culture types and its concentration was approximately 16 μg/ml. In the oxLDL-treated B104 neuroblastoma cell cultures 75% cells died after the 24-h exposure. The intact cells showed impaired mitochondria at the ultrastructural level. Western blot analysis revealed the increased expression of AIF 57 kDa (AIF(57)) protein, as a sign of caspase-independent cell death. In RN22 schwannoma cell cultures, oxLDL did not have any effect on cleaved caspase-3 and AIF(57) protein levels indicating absence of cell death. Treated RN22 schwannoma cells underwent survival autophagy by forming conspicuous autophagosomes and by processing LC3-I into LC3-II protein. Collectively, oxLDL induces AIF-dependent cell death in B104 neuroblastoma cells whereas in RN22 schwannoma cells enhanced signs of survival autophagy are noted.
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