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Pan T, Liu F, Hao X, Wang S, Wasi M, Song JH, Lewis VO, Lin PP, Moon B, Bird JE, Panaretakis T, Lin SH, Wu D, Farach-Carson MC, Wang L, Zhang N, An Z, Zhang XHF, Satcher RL. BIGH3 mediates apoptosis and gap junction failure in osteocytes during renal cell carcinoma bone metastasis progression. Cancer Lett 2024; 596:217009. [PMID: 38849015 DOI: 10.1016/j.canlet.2024.217009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 05/26/2024] [Accepted: 05/30/2024] [Indexed: 06/09/2024]
Abstract
Renal cell carcinoma (RCC) bone metastatis progression is driven by crosstalk between tumor cells and the bone microenvironment, which includes osteoblasts, osteoclasts, and osteocytes. RCC bone metastases (RCCBM) are predominantly osteolytic and resistant to antiresorptive therapy. The molecular mechanisms underlying pathologic osteolysis and disruption of bone homeostasis remain incompletely understood. We previously reported that BIGH3/TGFBI (transforming growth factor-beta-induced protein ig-h3, shortened to BIGH3 henceforth) secreted by colonizing RCC cells drives osteolysis by inhibiting osteoblast differentiation, impairing healing of osteolytic lesions, which is reversible with osteoanabolic agents. Here, we report that BIGH3 induces osteocyte apoptosis in both human RCCBM tissue specimens and in a preclinical mouse model. We also demonstrate that BIGH3 reduces Cx43 expression, blocking gap junction (GJ) function and osteocyte network communication. BIGH3-mediated GJ inhibition is blocked by the lysosomal inhibitor hydroxychloroquine (HCQ), but not osteoanabolic agents. Our results broaden the understanding of pathologic osteolysis in RCCBM and indicate that targeting the BIGH3 mechanism could be a combinational strategy for the treatment of RCCBM-induced bone disease that overcomes the limited efficacy of antiresorptives that target osteoclasts.
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Affiliation(s)
- Tianhong Pan
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Fengshuo Liu
- Departments of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Xiaoxin Hao
- Departments of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Shubo Wang
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Murtaza Wasi
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Jian H Song
- Departments of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Valerae O Lewis
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Patrick P Lin
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Bryan Moon
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Justin E Bird
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Theocharis Panaretakis
- Departments of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sue-Hwa Lin
- Departments of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; Departments of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Danielle Wu
- Department of Diagnostic and Biomedical Sciences, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX, USA; Departments of Bioengineering, Rice University, Houston, TX, USA
| | - Mary C Farach-Carson
- Department of Diagnostic and Biomedical Sciences, The University of Texas Health Science Center at Houston, School of Dentistry, Houston, TX, USA; Departments of BioSciences, Rice University, Houston, TX, USA; Departments of Bioengineering, Rice University, Houston, TX, USA
| | - Liyun Wang
- Department of Mechanical Engineering, University of Delaware, Newark, DE, USA
| | - Ningyan Zhang
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, USA
| | - Zhiqiang An
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, USA
| | - Xiang H-F Zhang
- Departments of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA; Departments of Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, USA; Departments of Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA; Departments of McNair Medical Institute, Baylor College of Medicine, Houston, TX, USA
| | - Robert L Satcher
- Departments of Orthopedic Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Sheng X, Zhang C, Zhao J, Xu J, Zhang P, Ding Q, Zhang J. Microvascular destabilization and intricated network of the cytokines in diabetic retinopathy: from the perspective of cellular and molecular components. Cell Biosci 2024; 14:85. [PMID: 38937783 PMCID: PMC11212265 DOI: 10.1186/s13578-024-01269-7] [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: 04/18/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024] Open
Abstract
Microvascular destabilization is the primary cause of the inner blood-retinal barrier (iBRB) breakdown and increased vascular leakage in diabetic retinopathy (DR). Microvascular destabilization results from the combinational effects of increased levels of growth factors and cytokines, involvement of inflammation, and the changed cell-to-cell interactions, especially the loss of endothelial cells and pericytes, due to hyperglycemia and hypoxia. As the manifestation of microvascular destabilization, the fluid transports via paracellular and transcellular routes increase due to the disruption of endothelial intercellular junctional complexes and/or the altered caveolar transcellular transport across the retinal vascular endothelium. With diabetes progression, the functional and the structural changes of the iBRB components, including the cellular and noncellular components, further facilitate and aggravate microvascular destabilization, resulting in macular edema, the neuroretinal damage and the dysfunction of retinal inner neurovascular unit (iNVU). Although there have been considerable recent advances towards a better understanding of the complex cellular and molecular network underlying the microvascular destabilization, some still remain to be fully elucidated. Recent data indicate that targeting the intricate signaling pathways may allow to against the microvascular destabilization. Therefore, efforts have been made to better clarify the cellular and molecular mechanisms that are involved in the microvascular destabilization in DR. In this review, we discuss: (1) the brief introduction of DR and microvascular destabilization; (2) the cellular and molecular components of iBRB and iNVU, and the breakdown of iBRB; (3) the matrix and cell-to-cell contacts to maintain microvascular stabilization, including the endothelial glycocalyx, basement membrane, and various cell-cell interactions; (4) the molecular mechanisms mediated cell-cell contacts and vascular cell death; (5) the altered cytokines and signaling pathways as well as the intricate network of the cytokines involved in microvascular destabilization. This comprehensive review aimed to provide the insights for microvascular destabilization by targeting the key molecules or specific iBRB cells, thus restoring the function and structure of iBRB and iNVU, to treat DR.
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Affiliation(s)
- Xia Sheng
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China
| | - Chunmei Zhang
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China
| | - Jiwei Zhao
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China
| | - Jianping Xu
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China.
| | - Peng Zhang
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China.
| | - Quanju Ding
- People's Hospital of Huangdao District, Qingdao, Shandong Province, China.
| | - Jingfa Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, National Clinical Research Center for Eye Diseases, Shanghai, China.
- The International Eye Research Institute of The Chinese University of Hong Kong (Shenzhen), Shenzhen, China.
- C-MER (Shenzhen) Dennis Lam Eye Hospital, Shenzhen, China.
- C-MER International Eye Care Group, C-MER Dennis Lam & Partners Eye Center, Hong Kong, China.
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Callan A, Jha S, Valdez L, Baldado L, Tsin A. TGF-β Signaling Pathways in the Development of Diabetic Retinopathy. Int J Mol Sci 2024; 25:3052. [PMID: 38474297 PMCID: PMC10932130 DOI: 10.3390/ijms25053052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 03/14/2024] Open
Abstract
Diabetic retinopathy (DR), a prevalent complication of diabetes mellitus affecting a significant portion of the global population, has long been viewed primarily as a microvascular disorder. However, emerging evidence suggests that it should be redefined as a neurovascular disease with multifaceted pathogenesis rooted in oxidative stress and advanced glycation end products. The transforming growth factor-β (TGF-β) signaling family has emerged as a major contributor to DR pathogenesis due to its pivotal role in retinal vascular homeostasis, endothelial cell barrier function, and pericyte differentiation. However, the precise roles of TGF-β signaling in DR remain incompletely understood, with conflicting reports on its impact in different stages of the disease. Additionally, the BMP subfamily within the TGF-β superfamily introduces further complexity, with BMPs exhibiting both pro- and anti-angiogenic properties. Furthermore, TGF-β signaling extends beyond the vascular realm, encompassing immune regulation, neuronal survival, and maintenance. The intricate interactions between TGF-β and reactive oxygen species (ROS), non-coding RNAs, and inflammatory mediators have been implicated in the pathogenesis of DR. This review delves into the complex web of signaling pathways orchestrated by the TGF-β superfamily and their involvement in DR. A comprehensive understanding of these pathways may hold the key to developing targeted therapies to halt or mitigate the progression of DR and its devastating consequences.
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Affiliation(s)
| | | | | | | | - Andrew Tsin
- School of Medicine, The University of Texas Rio Grande Valley, Edinburg, TX 78539, USA; (A.C.); (S.J.); (L.V.); (L.B.)
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Gao XW, Hu HL, Xie MH, Tang CX, Ou J, Lu ZH. CX3CL1/CX3CR1 axis alleviates inflammation and apoptosis in human nucleus pulpous cells via M2 macrophage polarization. Exp Ther Med 2023; 26:359. [PMID: 37324510 PMCID: PMC10265713 DOI: 10.3892/etm.2023.12058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 04/06/2023] [Indexed: 06/17/2023] Open
Abstract
CX3C chemokine ligand 1 (CX3CL1) belongs to the CX3C chemokine family and is involved in various disease processes. However, its role in intervertebral disc degeneration (IDD) remains to be elucidated. In the present study, western blotting, reverse transcription-quantitative PCR and ELISA assays were used to assess target gene expression. In addition, immunofluorescence and TUNEL staining were used to assess macrophage infiltration, monocyte migration and apoptosis. The present study aimed to reveal if and how CX3CL1 regulates IDD progression by exploring its effect on macrophage polarization and apoptosis of human nucleus pulposus cells (HNPCs). The data showed that CX3CL1 bound to CX3C motif chemokine receptor 1 (CX3CR1) promoted the M2 phenotype polarization via JAK2/STAT3 signaling, followed by increasing the secretion of anti-inflammatory cytokines from HNPCs. In addition, HNPC-derived CX3CL1 promoted M2 macrophage-derived C-C motif chemokine ligand 17 release thereby reducing the apoptosis of HNPCs. In clinic, the reduction of mRNA and protein levels CX3CL1 in degenerative nucleus pulposus tissues (NPs) was measured. Increased M1 macrophages and pro-inflammatory cytokines were found in NPs of IDD patients with low CX3CL1 expression. Collectively, these findings suggested that the CX3CL1/CX3CR1 axis alleviates IDD by reducing inflammation and apoptosis of HNPCs via macrophages. Therefore, targeting CX3CL1/CX3CR1 axis is expected to produce a new therapeutic approach for IDD.
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Affiliation(s)
- Xiao-Wen Gao
- The Department of Spinal Surgery, Affiliated Nanhua Hospital, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Han-Lin Hu
- The Department of Spinal Surgery, Affiliated Nanhua Hospital, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Ming-Hua Xie
- The Department of Spinal Surgery, Affiliated Nanhua Hospital, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Cai-Xia Tang
- The Department of Obstetrics and Gynecology, Affiliated Nanhua Hospital, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Jun Ou
- The Department of Spinal Surgery, Affiliated Nanhua Hospital, University of South China, Hengyang, Hunan 421001, P.R. China
| | - Zheng-Hao Lu
- The Department of Spinal Surgery, Affiliated Nanhua Hospital, University of South China, Hengyang, Hunan 421001, P.R. China
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Incomplete Recovery of Zebrafish Retina Following Cryoinjury. Cells 2022; 11:cells11081373. [PMID: 35456052 PMCID: PMC9030934 DOI: 10.3390/cells11081373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 02/05/2023] Open
Abstract
Zebrafish show an extraordinary potential for regeneration in several organs from fins to central nervous system. Most impressively, the outcome of an injury results in a near perfect regeneration and a full functional recovery. Indeed, among the various injury paradigms previously tested in the field of zebrafish retina regeneration, a perfect layered structure is observed after one month of recovery in most of the reported cases. In this study, we applied cryoinjury to the zebrafish eye. We show that retina exposed to this treatment for one second undergoes an acute damage affecting all retinal cell types, followed by a phase of limited tissue remodeling and regrowth. Surprisingly, zebrafish developed a persistent retinal dysplasia observable through 300 days post-injury. There is no indication of fibrosis during the regeneration period, contrary to the regeneration process after cryoinjury to the zebrafish cardiac ventricle. RNA sequencing analysis of injured retinas at different time points has uncovered enriched processes and a number of potential candidate genes. By means of this simple, time and cost-effective technique, we propose a zebrafish injury model that displays a unique inability to completely recover following focal retinal damage; an outcome that is unreported to our knowledge. Furthermore, RNA sequencing proved to be useful in identifying pathways, which may play a crucial role not only in the regeneration of the retina, but in the first initial step of regeneration, degeneration. We propose that this model may prove useful in comparative and translational studies to examine critical pathways for successful regeneration.
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Caprnda M, Kubatka P, Saxena S, Valaskova J, Stefanickova J, Kobyliak N, Zulli A, Kruzliak P. The Impact of Hyperglycemia on VEGF Secretion in Retinal Endothelial Cells. Folia Med (Plovdiv) 2019; 59:183-189. [PMID: 28704181 DOI: 10.1515/folmed-2017-0029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 12/21/2016] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Diabetic retinopathy is a serious sight-threatening complication which is manifested by excessive angiogenesis in diabetic patients. AIM We hypothesize that cultured Rhesus monkey retinal endothelial cells (RhRECs) respond to high glucose with a change in cell proliferation and vascular endothelial growth factor (VEGF) secretion. MATERIALS AND METHODS In our study, 20 000 cells per well were treated without glucose or with 5.5 mM, 18.5 mM and 30 mM glucose for 24 hours. Viable cells were counted using trypan blue dye exclusion method. VEGF concentrations were measured in cell media by ELISA method. RESULTS The number of viable cells incubated with 5.5 mM glucose increased significantly by 53.7% after 24 hours. In comparison, the number of viable cells decreased by 2.8% at 18.5 mM of glucose and by 20.4% at 30 mM of glucose after 24 hours of incubation. In contrast to this effect of glucose on the number of viable cells, a significant increase in VEGF levels (pg/mL) in the cell media with a glucose concentration of 0 mM compared to 5.5 mM of glucose was found. VEGF secretion in cell medium with 18.5 and 30 mM of glucose increased non-significantly in comparison with euglycemic levels. CONCLUSION Our results show that viability of retinal endothelial cells and VEGF release are highly responsive to changes in glucose concentration. Such glucose-induced changes in retinal endothelial cells may negatively impact the integrity of the microvasculature in the diabetic retina leading to angiogenesis and microaneursym.
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Affiliation(s)
- Martin Caprnda
- First Department of Internal Medicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Peter Kubatka
- Department of Medical Biology, Jessenius Faculty of Medicine, Comenius University in Bratislava, Martin, Slovak Republic
| | - Sandeep Saxena
- Retina service, Department of Ophthalmology, King George’s Medical University, Lucknow, India
| | - Jela Valaskova
- Department of Ophthalmology, Faculty of Medicine, Comenius University and University Hospital, Bratislava, Slovakia
| | - Jana Stefanickova
- Department of Ophthalmology, Faculty of Medicine, Comenius University and University Hospital, Bratislava, Slovakia
| | - Nazarii Kobyliak
- Endocrinology Department, Bogomolets National Medical University, Kyiv, Ukraine
| | - Anthony Zulli
- Centre for Chronic Disease (CCD), College of Health & Biomedicine, Victoria University, Melbourne, Victoria, Australia
| | - Peter Kruzliak
- Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno, Czech
Republic
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Malek G, Busik J, Grant MB, Choudhary M. Models of retinal diseases and their applicability in drug discovery. Expert Opin Drug Discov 2018; 13:359-377. [PMID: 29382242 DOI: 10.1080/17460441.2018.1430136] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The impact of vision debilitating diseases is a global public health concern, which will continue until effective preventative and management protocols are developed. Two retinal diseases responsible for the majority of vision loss in the working age adults and elderly populations are diabetic retinopathy (DR) and age-related macular degeneration (AMD), respectively. Model systems, which recapitulate aspects of human pathology, are valid experimental modalities that have contributed to the identification of signaling pathways involved in disease development and consequently potential therapies. Areas covered: The pathology of DR and AMD, which serve as the basis for designing appropriate models of disease, is discussed. The authors also review in vitro and in vivo models of DR and AMD and evaluate the utility of these models in exploratory and pre-clinical studies. Expert opinion: The complex nature of non-Mendelian diseases such as DR and AMD has made identification of effective therapeutic treatments challenging. However, the authors believe that while in vivo models are often criticized for not being a 'perfect' recapitulation of disease, they have been valuable experimentally when used with consideration of the strengths and limitations of the experimental model selected and have a place in the drug discovery process.
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Affiliation(s)
- Goldis Malek
- a Department of Ophthalmology , Duke University School of Medicine , Durham , NC , USA.,b Department of Pathology , Duke University School of Medicine , Durham , NC , USA
| | - Julia Busik
- c Department of Physiology , Michigan State University , East Lansing , MI , USA
| | - Maria B Grant
- d Department of Ophthalmology , University of Alabama at Birmingham , Birmingham , Al , USA
| | - Mayur Choudhary
- a Department of Ophthalmology , Duke University School of Medicine , Durham , NC , USA
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A Critical Analysis of the Available In Vitro and Ex Vivo Methods to Study Retinal Angiogenesis. J Ophthalmol 2017; 2017:3034953. [PMID: 28848677 PMCID: PMC5564124 DOI: 10.1155/2017/3034953] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/20/2017] [Accepted: 06/28/2017] [Indexed: 12/15/2022] Open
Abstract
Angiogenesis is a biological process with a central role in retinal diseases. The choice of the ideal method to study angiogenesis, particularly in the retina, remains a problem. Angiogenesis can be assessed through in vitro and in vivo studies. In spite of inherent limitations, in vitro studies are faster, easier to perform and quantify, and typically less expensive and allow the study of isolated angiogenesis steps. We performed a systematic review of PubMed searching for original articles that applied in vitro or ex vivo angiogenic retinal assays until May 2017, presenting the available assays and discussing their applicability, advantages, and disadvantages. Most of the studies evaluated migration, proliferation, and tube formation of endothelial cells in response to inhibitory or stimulatory compounds. Other aspects of angiogenesis were studied by assessing cell permeability, adhesion, or apoptosis, as well as by implementing organotypic models of the retina. Emphasis is placed on how the methods are applied and how they can contribute to retinal angiogenesis comprehension. We also discuss how to choose the best cell culture to implement these methods. When applied together, in vitro and ex vivo studies constitute a powerful tool to improve retinal angiogenesis knowledge. This review provides support for researchers to better select the most suitable protocols in this field.
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Mukhi D, Nishad R, Menon RK, Pasupulati AK. Novel Actions of Growth Hormone in Podocytes: Implications for Diabetic Nephropathy. Front Med (Lausanne) 2017; 4:102. [PMID: 28748185 PMCID: PMC5506074 DOI: 10.3389/fmed.2017.00102] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 06/26/2017] [Indexed: 02/05/2023] Open
Abstract
The kidney regulates water, electrolyte, and acid-base balance and thus maintains body homeostasis. The kidney’s potential to ensure ultrafiltered and almost protein-free urine is compromised in various metabolic and hormonal disorders such as diabetes mellitus (DM). Diabetic nephropathy (DN) accounts for ~20–40% of mortality in DM. Proteinuria, a hallmark of renal glomerular diseases, indicates injury to the glomerular filtration barrier (GFB). The GFB is composed of glomerular endothelium, basement membrane, and podocytes. Podocytes are terminally differentiated epithelial cells with limited ability to replicate. Podocyte shape and number are both critical for the integrity and function of the GFB. Podocytes are vulnerable to various noxious stimuli prevalent in a diabetic milieu that could provoke podocytes to undergo changes to their unique architecture and function. Effacement of podocyte foot process is a typical morphological alteration associated with proteinuria. The dedifferentiation of podocytes from epithelial-to-mesenchymal phenotype and consequential loss results in proteinuria. Poorly controlled type 1 DM is associated with elevated levels of circulating growth hormone (GH), which is implicated in the pathophysiology of various diabetic complications including DN. Recent studies demonstrate that functional GH receptors are expressed in podocytes and that GH may exert detrimental effects on the podocyte. In this review, we summarize recent advances that shed light on actions of GH on the podocyte that could play a role in the pathogenesis of DN.
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Affiliation(s)
- Dhanunjay Mukhi
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Rajkishor Nishad
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Ram K Menon
- Department of Pediatric Endocrinology and Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Anil Kumar Pasupulati
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
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Moritz RJ, LeBaron RG, Phelix CF, Rupaimoole R, Kim HS, Tsin A, Asmis R. Macrophage TGF- β1 and the Proapoptotic Extracellular Matrix Protein BIGH3 Induce Renal Cell Apoptosis in Prediabetic and Diabetic Conditions. ACTA ACUST UNITED AC 2017; 7:496-510. [PMID: 28149671 PMCID: PMC5279341 DOI: 10.4236/ijcm.2016.77055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Metabolically stressed kidney is in part characterized by infiltrating macrophages and macrophage-derived TGF-β1 that promote the synthesis of various ECM molecules. TGF-β1 strongly enhances the expression of the gene TGFBI that encodes a cell-adhesion class, proapoptotic ECM protein called BIGH3. We hypothesized that in a diabetic environment a relationship between infiltrating macrophages, macrophage-derived TGF-β1, and BIGH3 protein promotes renal cell death. To investigate this hypothesis, we used our mouse model of diabetic complications. Mice on a high-fat diet developed hypercholesterolemia, and exposure to streptozotocin rendered hypercholesterolemic mice diabetic. Immunohistochemical images show increased macrophage infiltration and BIGH3 protein in the kidney cortices of hypercholesterolemic and diabetic mice. Macrophages induced a two-fold increase in BIGH3 expression and an 86% increase in renal proximal tubule epithelial cell apoptosis. TGF-β1 antibody and TGF-β1 receptor chemical antagonist blocked macrophage-induced apoptosis. BIGH3 antibody completely blocked apoptosis that was induced by TGF-β1, and blocked apoptosis induced by exogenous recombinant BIGH3. These results uncover a distinctive interplay of macrophage-derived TGF-β1, BIGH3 protein, and apoptosis, and indicate that BIGH3 is central in a novel pathway that promotes diabetic nephropathy. Macrophage TGF-β1 and BIGH3 are identified as prediabetic biomarkers, and potential therapeutic targets for intervention in prediabetic and diabetic individuals.
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Affiliation(s)
- Robert J Moritz
- Department of Biology, University of Texas at San Antonio, San Antonio, USA
| | - Richard G LeBaron
- Department of Biology, University of Texas at San Antonio, San Antonio, USA
| | - Clyde F Phelix
- Department of Biology, University of Texas at San Antonio, San Antonio, USA
| | - Rajesha Rupaimoole
- Department of Biology, University of Texas at San Antonio, San Antonio, USA
| | - Hong Seok Kim
- Departments of Biochemistry and Clinical Laboratory Sciences, School of Health Professions, University of Texas Health Science Center at San Antonio, San Antonio, USA
| | - Andrew Tsin
- Department of Biology, University of Texas at San Antonio, San Antonio, USA
| | - Reto Asmis
- Departments of Biochemistry and Clinical Laboratory Sciences, School of Health Professions, University of Texas Health Science Center at San Antonio, San Antonio, USA
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TGFβ induces BIGH3 expression and human retinal pericyte apoptosis: a novel pathway of diabetic retinopathy. Eye (Lond) 2016; 30:1639-1647. [PMID: 27564721 DOI: 10.1038/eye.2016.179] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 06/14/2016] [Indexed: 02/05/2023] Open
Abstract
PurposeOne of the earliest hallmarks of diabetic retinopathy is the loss of retinal pericytes. However, the mechanisms that promote pericyte dropout are unknown. In the present study, we propose a novel pathway in which pericyte apoptosis is mediated by macrophages, TGFβ and pro-apoptotic BIGH3 (TGFβ-induced Gene Human Clone 3) protein.Patients and methodsTo elucidate this pathway, we assayed human retinal pericyte (HRP) apoptosis by TUNEL assay, BIGH3 mRNA expression by qPCR, and BIGH3 protein expression by western blot analysis. HRP were treated with BIGH3 protein, TGFβ1 and TGFβ2 and inhibition assays were carried out by blocking with antibodies against BIGH3. The distribution of BIGH3 and CD68+ macrophages were compared in a post-mortem donor eye with 7-year history of Type II diabetes and histopathogically confirmed non-proliferative diabetic retinopathy (NPDR).ResultsTGFβ induced a significant increase in BIGH3 mRNA and protein expression, and HRP apoptosis. BIGH3 treatment showed HRP undergo apoptosis in a dose-dependent manner. At 5 μg/ml, BIGH3 induced 3.5-times more apoptosis in HRP than in retinal endothelial cells. TGFβ induced apoptosis was inhibited by blocking with antibodies against BIGH3. In an example of NPDR, BIGH3 accumulated within the walls of the inner retina arterioles. Macrophage infiltrates were frequently associated with these vessels and the inner nuclear layer.ConclusionTogether with our previously published results on macrophage-induced retinal endothelial cell apoptosis, the present study supports a novel inflammatory pathway mediated by macrophages and the BIGH3 protein leading to HRP apoptosis. As shown in human post-mortem globes, these observations are clinically relevant, suggesting a new mechanism underlying pericyte dropout during NPDR.
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Betts-Obregon BS, Vellanki S, Buikema J, Tsin AT, Wright K. Effect of Glucose on Retinal Endothelial Cell Viability and VEGF Secretion. HSOA JOURNAL OF CELL BIOLOGY & CELL METABOLISM 2016; 3:008. [PMID: 27833938 PMCID: PMC5100359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Previous studies have shown that in diabetic patients, there is an increase of retinal capillaries associated with the development of diabetic retinopathy in the eye. The objective of current study is to investigate the effect of glucose on retinal endothelial cell viability and VEGF secretion. 20,000 cells per well were treated without glucose or with 5.5mM (euglycemic), 18.5mM and 30mM (hyperglycemic) glucose for 24 hours. Viable cells were counted using Trypan blue dye exclusion method. ELISA was used to measure VEGF secretion from cells into the cell medium. The number of viable cells incubated with 5.5mM glucose (physiological control) increased by 53.7% after 24 hours. In comparison, cells treated with 18.5mM glucose decreased by 2.8% while cells treated with 30mM glucose decreased by 20% after 24 hours of incubation. Cells without glucose treatment (0mM control) decreased by 33.3%. In contrast to the decrease of viable cell numbers after treatment with high glucose, there is an increase in VEGF secretion (pg/mL) to the cell medium with increase in glucose concentration from 5.5mM to 0, 18.5, and 30mM. The amount of VEGF secreted per cell also increased with increasing glucose concentrations. Our results show that viability of retinal endothelial cells and VEGF release are highly responsive to changes in glucose concentration. Such glucose-induced changes in retinal endothelial cells may negatively impact the integrity of the microvasculature in the diabetic retina leading to angiogenesis and microaneursyms.
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Affiliation(s)
| | - Sandeep Vellanki
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Jessica Buikema
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Andrew T Tsin
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Keli Wright
- Department of Biology, Oakwood University, Huntsville, AL, USA
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