1
|
Shen H, Yuan J, Tong D, Chen B, Yu E, Chen G, Peng C, Chang W, E J, Cao F. Regulator of G protein signaling 16 restrains apoptosis in colorectal cancer through disrupting TRAF6-TAB2-TAK1-JNK/p38 MAPK signaling. Cell Death Dis 2024; 15:438. [PMID: 38906869 PMCID: PMC11192724 DOI: 10.1038/s41419-024-06803-6] [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: 02/17/2024] [Revised: 05/28/2024] [Accepted: 05/31/2024] [Indexed: 06/23/2024]
Abstract
Colorectal cancer (CRC) remains a major global cause of cancer-related mortality, lacking effective biomarkers and therapeutic targets. Revealing the critical pathogenic factors of CRC and the underlying mechanisms would offer potential therapeutic strategies for clinical application. G protein signaling (RGS) protein family modulators play essential role within regulating downstream signaling of GPCR receptors, with function in cancers unclear. Our study focused on the expression patterns of RGS proteins in CRC, identifying Regulator of G protein signaling 16 (RGS16) as a prospective diagnostic and therapeutic target. Analyzing 899 CRC tissues revealed elevated RGS16 levels, correlating with clinicopathological features and CRC prognosis by immunohistochemistry (IHC) combined with microarray. We confirmed the elevated RGS16 protein level in CRC, and found that patients with RGS16-high tumors exhibited decreased disease-specific survival (DSS) and disease-free survival (DFS) compared to those with low RGS16 expression. Functional assays demonstrated that RGS16 promoted the CRC progression, knockdown of RGS16 led to significantly increased apoptosis rates of CRC in vitro and in vivo. Notably, we also confirmed these phenotypes of RGS16 in organoids originated from resected primary human CRC tissues. Mechanistically, RGS16 restrained JNK/P38-mediated apoptosis in CRC cells through disrupting the recruitment of TAB2/TAK1 to TRAF6. This study provides insights into addressing the challenges posed by CRC, offering avenues for clinical translation.
Collapse
Affiliation(s)
- Hao Shen
- Department of Colorectal Surgery, The First Affiliated Hospital of Naval Medical University, Shanghai, China
- Department of Environmental and Occupational Health, Naval Medical University, Shanghai, China
| | - Jie Yuan
- Department of Colorectal Surgery, The First Affiliated Hospital of Naval Medical University, Shanghai, China
- Department of Health Management, Beidaihe Rest and Recuperation Center of PLA Joint Logistics Support Force, Qinhuangdao, China
| | - Dafeng Tong
- Department of Colorectal Surgery, The First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Bingchen Chen
- Department of Colorectal Surgery, The First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Enda Yu
- Department of Colorectal Surgery, The First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Guanglei Chen
- Department of Health Management, Beidaihe Rest and Recuperation Center of PLA Joint Logistics Support Force, Qinhuangdao, China
| | - Cheng Peng
- Department of Health Management, Beidaihe Rest and Recuperation Center of PLA Joint Logistics Support Force, Qinhuangdao, China
| | - Wenjun Chang
- Department of Environmental and Occupational Health, Naval Medical University, Shanghai, China.
| | - Jifu E
- Department of Colorectal Surgery, The First Affiliated Hospital of Naval Medical University, Shanghai, China.
| | - Fuao Cao
- Department of Colorectal Surgery, The First Affiliated Hospital of Naval Medical University, Shanghai, China.
| |
Collapse
|
2
|
Sengar AS, Kumar M, Rai C, Chakraborti S, Kumar D, Kumar P, Mukherjee S, Mondal K, Stewart A, Maity B. RGS6 drives cardiomyocyte death following nucleolar stress by suppressing Nucleolin/miRNA-21. J Transl Med 2024; 22:204. [PMID: 38409136 PMCID: PMC10895901 DOI: 10.1186/s12967-024-04985-3] [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: 11/26/2023] [Accepted: 02/12/2024] [Indexed: 02/28/2024] Open
Abstract
BACKGROUND Prior evidence demonstrated that Regulator of G protein Signaling 6 (RGS6) translocates to the nucleolus in response to cytotoxic stress though the functional significance of this phenomenon remains unknown. METHODS Utilizing in vivo gene manipulations in mice, primary murine cardiac cells, human cell lines and human patient samples we dissect the participation of a RGS6-nucleolin complex in chemotherapy-dependent cardiotoxicity. RESULTS Here we demonstrate that RGS6 binds to a key nucleolar protein, Nucleolin, and controls its expression and activity in cardiomyocytes. In the human myocyte AC-16 cell line, induced pluripotent stem cell derived cardiomyocytes, primary murine cardiomyocytes, and the intact murine myocardium tuning RGS6 levels via overexpression or knockdown resulted in diametrically opposed impacts on Nucleolin mRNA, protein, and phosphorylation.RGS6 depletion provided marked protection against nucleolar stress-mediated cell death in vitro, and, conversely, RGS6 overexpression suppressed ribosomal RNA production, a key output of the nucleolus, and triggered death of myocytes. Importantly, overexpression of either Nucleolin or Nucleolin effector miRNA-21 counteracted the pro-apoptotic effects of RGS6. In both human and murine heart tissue, exposure to the genotoxic stressor doxorubicin was associated with an increase in the ratio of RGS6/Nucleolin. Preventing RGS6 induction via introduction of RGS6-directed shRNA via intracardiac injection proved cardioprotective in mice and was accompanied by restored Nucleolin/miRNA-21 expression, decreased nucleolar stress, and decreased expression of pro-apoptotic, hypertrophy, and oxidative stress markers in heart. CONCLUSION Together, these data implicate RGS6 as a driver of nucleolar stress-dependent cell death in cardiomyocytes via its ability to modulate Nucleolin. This work represents the first demonstration of a functional role for an RGS protein in the nucleolus and identifies the RGS6/Nucleolin interaction as a possible new therapeutic target in the prevention of cardiotoxicity.
Collapse
Affiliation(s)
- Abhishek Singh Sengar
- Centre of Biomedical Research (CBMR), SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Manish Kumar
- Centre of Biomedical Research (CBMR), SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Chetna Rai
- Centre of Biomedical Research (CBMR), SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Sreemoyee Chakraborti
- Centre of Biomedical Research (CBMR), SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
- Forensic Science Laboratory, Department of Home and Hill Affairs, Kolkata, West Bengal, 700037, India
| | - Dinesh Kumar
- Centre of Biomedical Research (CBMR), SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Pranesh Kumar
- Institute of Pharmaceutical Science, University of Lucknow, Lucknow, Uttar Pradesh, 226007, India
| | - Sukhes Mukherjee
- Biochemistry, AIIMS Bhopal, Saket Nagar, Bhopal, Madhya Pradesh, 462026, India
| | - Kausik Mondal
- Zoology, University of Kalyani, Nadia, West Bengal, 741235, India
| | - Adele Stewart
- Biomedical Science, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Biswanath Maity
- Centre of Biomedical Research (CBMR), SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India.
| |
Collapse
|
3
|
Song J, Li M, Chen C, Zhou J, Wang L, Yan Y, She J, Tong L, Song Y. Regulator of G protein signaling protein 6 alleviates acute lung injury by inhibiting inflammation and promoting cell self-renewal in mice. Cell Mol Biol Lett 2023; 28:102. [PMID: 38066447 PMCID: PMC10709870 DOI: 10.1186/s11658-023-00488-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Accepted: 09/08/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Acute respiratory distress syndrome (ARDS) is a disease with high mortality and morbidity. Regulator of G protein signaling protein 6 (RGS6), identified as a tumor suppressor gene, has received increasing attention owing to its close relationship with oxidative stress and inflammation. However, the association between ARDS and RGS6 has not been reported. METHODS Congruously regulated G protein-coupled receptor (GPCR)-related genes and differentially expressed genes (DEGs) in an acute lung injury (ALI) model were identified, and functional enrichment analysis was conducted. In an in vivo study, the effects of RGS6 knockout were studied in a mouse model of ALI induced by lipopolysaccharide (LPS). HE staining, ELISA, and immunohistochemistry were used to evaluate pathological changes and the degree of inflammation. In vitro, qRT‒PCR, immunofluorescence staining, and western blotting were used to determine the dynamic changes in RGS6 expression in cells. The RGS6 overexpression plasmid was constructed for transfection. qRT‒PCR was used to assess proinflammatory factors transcription. Western blotting and flow cytometry were used to evaluate apoptosis and reactive oxygen species (ROS) production. Organoid culture was used to assess the stemness and self-renewal capacity of alveolar epithelial type II cells (AEC2s). RESULTS A total of 110 congruously regulated genes (61 congruously upregulated and 49 congruously downregulated genes) were identified among GPCR-related genes and DEGs in the ALI model. RGS6 was downregulated in vivo and in vitro in the ALI model. RGS6 was expressed in the cytoplasm and accumulated in the nucleus after LPS stimulation. Compared with the control group, we found higher mortality, more pronounced body weight changes, more serious pulmonary edema and pathological damage, and more neutrophil infiltration in the RGS6 knockout group upon LPS stimulation in vivo. Moreover, AEC2s loss was significantly increased upon RGS6 knockout. Organoid culture assays showed slower alveolar organoid formation, fewer alveolar organoids, and impaired development of new structures after passaging upon RGS6 knockout. In addition, RGS6 overexpression decreased ROS production as well as proinflammatory factor transcription in macrophages and decreased apoptosis in epithelial cells. CONCLUSIONS RGS6 plays a protective role in ALI not only in early inflammatory responses but also in endogenous lung stem cell regeneration.
Collapse
Affiliation(s)
- Juan Song
- Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, 200032, China
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
- Department of Pulmonary Medicine, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, Fujian, 361000, China
- Shanghai Respiratory Research Institute, Shanghai, 200032, China
| | - Miao Li
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
- Shanghai Respiratory Research Institute, Shanghai, 200032, China
| | - Cuicui Chen
- Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, 200032, China
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
- Shanghai Respiratory Research Institute, Shanghai, 200032, China
| | - Jian Zhou
- Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, 200032, China
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
- Shanghai Respiratory Research Institute, Shanghai, 200032, China
| | - Linlin Wang
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
- Shanghai Respiratory Research Institute, Shanghai, 200032, China
| | - Yu Yan
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
- Shanghai Respiratory Research Institute, Shanghai, 200032, China
| | - Jun She
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
- Shanghai Respiratory Research Institute, Shanghai, 200032, China.
| | - Lin Tong
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
- Department of Pulmonary Medicine, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, Fujian, 361000, China.
- Shanghai Respiratory Research Institute, Shanghai, 200032, China.
| | - Yuanlin Song
- Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, 200032, China.
- Shanghai Key Laboratory of Lung Inflammation and Injury, Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
- Department of Pulmonary Medicine, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, Fujian, 361000, China.
- Shanghai Respiratory Research Institute, Shanghai, 200032, China.
| |
Collapse
|
4
|
Yang C, Zhang X, Yang X, Lian F, Sun Z, Huang Y, Shen W. Function and regulation of RGS family members in solid tumours: a comprehensive review. Cell Commun Signal 2023; 21:316. [PMID: 37924113 PMCID: PMC10623796 DOI: 10.1186/s12964-023-01334-7] [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: 05/10/2023] [Accepted: 09/25/2023] [Indexed: 11/06/2023] Open
Abstract
G protein-coupled receptors (GPCRs) play a key role in regulating the homeostasis of the internal environment and are closely associated with tumour progression as major mediators of cellular signalling. As a diverse and multifunctional group of proteins, the G protein signalling regulator (RGS) family was proven to be involved in the cellular transduction of GPCRs. Growing evidence has revealed dysregulation of RGS proteins as a common phenomenon and highlighted the key roles of these proteins in human cancers. Furthermore, their differential expression may be a potential biomarker for tumour diagnosis, treatment and prognosis. Most importantly, there are few systematic reviews on the functional/mechanistic characteristics and clinical application of RGS family members at present. In this review, we focus on the G-protein signalling regulator (RGS) family, which includes more than 20 family members. We analysed the classification, basic structure, and major functions of the RGS family members. Moreover, we summarize the expression changes of each RGS family member in various human cancers and their important roles in regulating cancer cell proliferation, stem cell maintenance, tumorigenesis and cancer metastasis. On this basis, we outline the molecular signalling pathways in which some RGS family members are involved in tumour progression. Finally, their potential application in the precise diagnosis, prognosis and treatment of different types of cancers and the main possible problems for clinical application at present are discussed. Our review provides a comprehensive understanding of the role and potential mechanisms of RGS in regulating tumour progression. Video Abstract.
Collapse
Affiliation(s)
- Chenglong Yang
- Key Laboratory of Precision Oncology in Universities of Shandong, Institute of Precision Medicine, Jining Medical University, Jining, 272067, China
| | - Xiaoyuan Zhang
- Key Laboratory of Precision Oncology in Universities of Shandong, Institute of Precision Medicine, Jining Medical University, Jining, 272067, China
| | - Xiaowen Yang
- Key Laboratory of Precision Oncology in Universities of Shandong, Institute of Precision Medicine, Jining Medical University, Jining, 272067, China
| | - Fuming Lian
- Key Laboratory of Precision Oncology in Universities of Shandong, Institute of Precision Medicine, Jining Medical University, Jining, 272067, China
| | - Zongrun Sun
- Key Laboratory of Precision Oncology in Universities of Shandong, Institute of Precision Medicine, Jining Medical University, Jining, 272067, China
| | - Yongming Huang
- Department of General Surgery, Affiliated Hospital of Jining Medical University, Jining Medical University, Jining, 272067, China.
| | - Wenzhi Shen
- Key Laboratory of Precision Oncology in Universities of Shandong, Institute of Precision Medicine, Jining Medical University, Jining, 272067, China.
| |
Collapse
|
5
|
Basak M, Das K, Mahata T, Kumar D, Nagar N, Poluri KM, Kumar P, Das P, Stewart A, Maity B. RGS7 balances acetylation/de-acetylation of p65 to control chemotherapy-dependent cardiac inflammation. Cell Mol Life Sci 2023; 80:255. [PMID: 37589751 PMCID: PMC11071981 DOI: 10.1007/s00018-023-04895-5] [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: 04/17/2023] [Revised: 06/28/2023] [Accepted: 07/22/2023] [Indexed: 08/18/2023]
Abstract
Cardiotoxicity remains a major limitation in the clinical utility of anthracycline chemotherapeutics. Regulator of G-protein Signaling 7 (RGS7) and inflammatory markers are up-regulated in the hearts of patients with a history of chemotherapy particularly those with reduced left-ventricular function. RGS7 knockdown in either the murine myocardium or isolated murine ventricular cardiac myocytes (VCM) or cultured human VCM provided marked protection against doxorubicin-dependent oxidative stress, NF-κB activation, inflammatory cytokine production, and cell death. In exploring possible mechanisms causally linking RGS7 to pro-inflammatory signaling cascades, we found that RGS7 forms a complex with acetylase Tip60 and deacetylase sirtuin 1 (SIRT1) and controls the acetylation status of the p65 subunit of NF-κB. In VCM, the detrimental impact of RGS7 could be mitigated by inhibiting Tip60 or activating SIRT1, indicating that the ability of RGS7 to modulate cellular acetylation capacity is critical for its pro-inflammatory actions. Further, RGS7-driven, Tip60/SIRT1-dependent cytokines released from ventricular cardiac myocytes and transplanted onto cardiac fibroblasts increased oxidative stress, markers of transdifferentiation, and activity of extracellular matrix remodelers emphasizing the importance of the RGS7-Tip60-SIRT1 complex in paracrine signaling in the myocardium. Importantly, while RGS7 overexpression in heart resulted in sterile inflammation, fibrotic remodeling, and compromised left-ventricular function, activation of SIRT1 counteracted the detrimental impact of RGS7 in heart confirming that RGS7 increases acetylation of SIRT1 substrates and thereby drives cardiac dysfunction. Together, our data identify RGS7 as an amplifier of inflammatory signaling in heart and possible therapeutic target in chemotherapeutic drug-induced cardiotoxicity.
Collapse
Affiliation(s)
- Madhuri Basak
- Centre of Biomedical Research (CBMR), SGPGI, SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Kiran Das
- Centre of Biomedical Research (CBMR), SGPGI, SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Tarun Mahata
- Centre of Biomedical Research (CBMR), SGPGI, SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Dinesh Kumar
- Centre of Biomedical Research (CBMR), SGPGI, SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Nupur Nagar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, 247667, India
| | - Krishna Mohan Poluri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, 247667, India
| | - Pranesh Kumar
- Institute of Pharmaceutical Sciences, University of Lucknow, Lucknow, Uttar Pradesh, 226025, India
| | - Priyadip Das
- Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur, Chennai, Tamilnadu, 603203, India
| | - Adele Stewart
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, 33458, USA.
| | - Biswanath Maity
- Centre of Biomedical Research (CBMR), SGPGI, SGPGI Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India.
| |
Collapse
|
6
|
Li L, Xu Q, Tang C. RGS proteins and their roles in cancer: friend or foe? Cancer Cell Int 2023; 23:81. [PMID: 37118788 PMCID: PMC10148553 DOI: 10.1186/s12935-023-02932-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/21/2023] [Indexed: 04/30/2023] Open
Abstract
As negative modulators of G-protein-coupled receptors (GPCRs) signaling, regulators of G protein signaling (RGS) proteins facilitate various downstream cellular signalings through regulating kinds of heterotrimeric G proteins by stimulating the guanosine triphosphatase (GTPase) activity of G-protein α (Gα) subunits. The expression of RGS proteins is dynamically and precisely mediated by several different mechanisms including epigenetic regulation, transcriptional regulation -and post-translational regulation. Emerging evidence has shown that RGS proteins act as important mediators in controlling essential cellular processes including cell proliferation, survival -and death via regulating downstream cellular signaling activities, indicating that RGS proteins are fundamentally involved in sustaining normal physiological functions and dysregulation of RGS proteins (such as aberrant expression of RGS proteins) is closely associated with pathologies of many diseases such as cancer. In this review, we summarize the molecular mechanisms governing the expression of RGS proteins, and further discuss the relationship of RGS proteins and cancer.
Collapse
Affiliation(s)
- Lin Li
- National Clinical Research Center for Child Health of the Children's Hospital, Zhejiang University School of Medicine, No. 3333, Binsheng Rd., Hangzhou, 310052, People's Republic of China
- Department of Urology, Third Affiliated Hospital of the Second Military Medical University, Shanghai, 201805, China
| | - Qiang Xu
- National Clinical Research Center for Child Health of the Children's Hospital, Zhejiang University School of Medicine, No. 3333, Binsheng Rd., Hangzhou, 310052, People's Republic of China
| | - Chao Tang
- National Clinical Research Center for Child Health of the Children's Hospital, Zhejiang University School of Medicine, No. 3333, Binsheng Rd., Hangzhou, 310052, People's Republic of China.
| |
Collapse
|
7
|
Sivagnanam S, Das K, Pan I, Barik A, Stewart A, Maity B, Das P. Functionalized Fluorescent Nanostructures Generated from Self-Assembly of a Cationic Tripeptide Direct Cell-Selective Chemotherapeutic Drug Delivery. ACS APPLIED BIO MATERIALS 2023; 6:836-847. [PMID: 36757106 DOI: 10.1021/acsabm.2c00996] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Nanodrug delivery systems (NDDs) capable of conveying chemotherapeutics directly into malignant cells without harming healthy ones are of significant interest in the field of cancer therapy. However, the development of nanostructures with the requisite biocompatibility, inherent optical properties, cellular penetration ability, encapsulation capability, and target selectivity has remained elusive. In an effort to develop cell-selective NDDs, we have synthesized a cationic tripeptide Boc-Arg-Trp-Phe-OMe (PA1), which self-assembles into well-ordered spheres in 100% aqueous medium. The inherent fluorescence properties of the peptide PA1 were shifted from the ultraviolet to the visible region by the self-assembly. These fluorescent nanostructures are proteolytically stable, photostable, and biocompatible, with characteristic blue fluorescence signals that permit us to monitor their intracellular entry in real time. We also demonstrate that these tripeptide spherical structures (TPSS) have the capacity to entrap the chemotherapeutic drug doxorubicin (Dox), shuttle the encapsulated drug within cancerous cells, and initiate the DNA damage signaling cascade, which culminates in apoptosis. Next, we functionalized the TPSS with an epithelial-cell-specific epithelial cell adhesion molecule aptamer. Aptamer-conjugated PA1 (PA1-Apt) facilitated efficient Dox delivery into the breast cancer epithelial cell line MCF7, resulting in cell death. However, cells of the human cardiomyocyte cell line AC16 were resistant to the cell killing actions of PA1-Apt. Together, these data demonstrate that not only can the self-assembly of cationic tripeptides like PA1 be exploited for efficient drug encapsulation and delivery but their unique chemistry also allows for functional modifications, which can improve the selectivity of these versatile NDDs.
Collapse
Affiliation(s)
- Subramaniyam Sivagnanam
- Department of Chemistry, SRM Institute of Science and Technology, SRM Nagar, Potheri, Kattankulathur 603203, Tamil Nadu, India
| | - Kiran Das
- Department of Systems Biology, Centre of Biomedical Research (CBMR), SGPGI Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India
| | - Ieshita Pan
- Department of Biotechnology, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 602105, Tamil Nadu, India
| | - Atanu Barik
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, Maharashtra, India
| | - Adele Stewart
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, Florida 33458, United States
| | - Biswanath Maity
- Department of Systems Biology, Centre of Biomedical Research (CBMR), SGPGI Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India
| | - Priyadip Das
- Department of Chemistry, SRM Institute of Science and Technology, SRM Nagar, Potheri, Kattankulathur 603203, Tamil Nadu, India
| |
Collapse
|
8
|
A RGS7-CaMKII complex drives myocyte-intrinsic and myocyte-extrinsic mechanisms of chemotherapy-induced cardiotoxicity. Proc Natl Acad Sci U S A 2023; 120:e2213537120. [PMID: 36574707 PMCID: PMC9910480 DOI: 10.1073/pnas.2213537120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Dose-limiting cardiotoxicity remains a major limitation in the clinical use of cancer chemotherapeutics. Here, we describe a role for Regulator of G protein Signaling 7 (RGS7) in chemotherapy-dependent heart damage, the demonstration for a functional role of RGS7 outside of the nervous system and retina. Though expressed at low levels basally, we observed robust up-regulation of RGS7 in the human and murine myocardium following chemotherapy exposure. In ventricular cardiomyocytes (VCM), RGS7 forms a complex with Ca2+/calmodulin-dependent protein kinase (CaMKII) supported by key residues (K412 and P391) in the RGS domain of RGS7. In VCM treated with chemotherapeutic drugs, RGS7 facilitates CaMKII oxidation and phosphorylation and CaMKII-dependent oxidative stress, mitochondrial dysfunction, and apoptosis. Cardiac-specific RGS7 knockdown protected the heart against chemotherapy-dependent oxidative stress, fibrosis, and myocyte loss and improved left ventricular function in mice treated with doxorubicin. Conversely, RGS7 overexpression induced fibrosis, reactive oxygen species generation, and cell death in the murine myocardium that were mitigated following CaMKII inhibition. RGS7 also drives production and release of the cardiokine neuregulin-1, which facilitates paracrine communication between VCM and neighboring vascular endothelial cells (EC), a maladaptive mechanism contributing to VCM dysfunction in the failing heart. Importantly, while RGS7 was both necessary and sufficient to facilitate chemotherapy-dependent cytotoxicity in VCM, RGS7 is dispensable for the cancer-killing actions of these same drugs. These selective myocyte-intrinsic and myocyte-extrinsic actions of RGS7 in heart identify RGS7 as an attractive therapeutic target in the mitigation of chemotherapy-driven cardiotoxicity.
Collapse
|
9
|
Basak M, Das K, Mahata T, Sengar AS, Verma SK, Biswas S, Bhadra K, Stewart A, Maity B. RGS7-ATF3-Tip60 Complex Promotes Hepatic Steatosis and Fibrosis by Directly Inducing TNFα. Antioxid Redox Signal 2023; 38:137-159. [PMID: 35521658 DOI: 10.1089/ars.2021.0174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Aims: The pathophysiological mechanism(s) underlying non-alcoholic fatty liver disease (NAFLD) have yet to be fully delineated and only a single drug, peroxisome proliferator-activated receptor (PPAR) α/γ agonist saroglitazar, has been approved. Here, we sought to investigate the role of Regulator of G Protein Signaling 7 (RGS7) in hyperlipidemia-dependent hepatic dysfunction. Results: RGS7 is elevated in the livers of NAFLD patients, particularly those with severe hepatic damage, pronounced insulin resistance, and high inflammation. In the liver, RGS7 forms a unique complex with transcription factor ATF3 and histone acetyltransferase Tip60, which is implicated in NAFLD. The removal of domains is necessary for ATF3/Tip60 binding compromises RGS7-dependent reactive oxygen species generation and cell death. Hepatic RGS7 knockdown (KD) prevented ATF3/Tip60 induction, and it provided protection against fibrotic remodeling and inflammation in high-fat diet-fed mice translating to improvements in liver function. Hyperlipidemia-dependent oxidative stress and metabolic dysfunction were largely reversed in RGS7 KD mice. Interestingly, saroglitazar failed to prevent RGS7/ATF3 upregulation but it did partially restore Tip60 levels. RGS7 drives the release of particularly tumor necrosis factor α (TNFα) from isolated hepatocytes, stellate cells and its depletion reverses steatosis, oxidative stress by direct TNFα exposure. Conversely, RGS7 overexpression in the liver is sufficient to trigger oxidative stress in hepatocytes that can be mitigated via TNFα inhibition. Innovation: We discovered a novel non-canonical function for an R7RGS protein, which usually functions to regulate G protein coupled receptor (GPCR) signaling. This is the first demonstration for a functional role of RGS7 outside the retina and central nervous system. Conclusion: RGS7 represents a potential novel target for the amelioration of NAFLD. Antioxid. Redox Signal. 38, 137-159.
Collapse
Affiliation(s)
| | - Kiran Das
- Centre of Biomedical Research, Lucknow, India
| | | | | | | | - Sayan Biswas
- Department of Forensic Medicine, College of Medicine and Sagore Dutta Hospital, Kolkata, India
| | - Kakali Bhadra
- Department of Zoology, University of Kalyani, Kalyani, India
| | - Adele Stewart
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, Florida, USA
| | | |
Collapse
|
10
|
Das K, Basak M, Mahata T, Kumar M, Kumar D, Biswas S, Chatterjee S, Moniruzzaman M, Saha NC, Mondal K, Kumar P, Das P, Stewart A, Maity B. RGS11-CaMKII complex mediated redox control attenuates chemotherapy-induced cardiac fibrosis. Redox Biol 2022; 57:102487. [PMID: 36228439 PMCID: PMC9557029 DOI: 10.1016/j.redox.2022.102487] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 09/20/2022] [Indexed: 12/06/2022] Open
Abstract
Dose limiting cardiotoxicity remains a major limiting factor in the clinical use of several cancer chemotherapeutics including anthracyclines and the antimetabolite 5-fluorouracil (5-FU). Prior work has demonstrated that chemotherapeutics increase expression of R7 family regulator of G protein signaling (RGS) protein-binding partner Gβ5, which drives myocyte cytotoxicity. However, though several R7 family members are expressed in heart, the exact role of each protein in chemotherapy driven heart damage remains unclear. Here, we demonstrate that RGS11, downregulated in the human heart following chemotherapy exposure, possesses potent anti-apoptotic actions, in direct opposition to the actions of fellow R7 family member RGS6. RGS11 forms a direct complex with the apoptotic kinase CaMKII and stress responsive transcription factor ATF3 and acts to counterbalance the ability of CaMKII and ATF3 to trigger oxidative stress, mitochondrial dysfunction, cell death, and release of the cardiokine neuregulin-1 (NRG1), which mediates pathological intercommunication between myocytes and endothelial cells. Doxorubicin triggers RGS11 depletion in the murine myocardium, and cardiac-specific OE of RGS11 decreases doxorubicin-induced fibrosis, myocyte hypertrophy, apoptosis, oxidative stress, and cell loss and aids in the maintenance of left ventricular function. Conversely, RGS11 knockdown in heart promotes cardiac fibrosis associated with CaMKII activation and ATF3/NRG1 induction. Indeed, inhibition of CaMKII largely prevents the fibrotic remodeling resulting from cardiac RGS11 depletion underscoring the functional importance of the RGS11-CaMKII interaction in the pathogenesis of cardiac fibrosis. These data describe an entirely new role for RGS11 in heart and identify RGS11 as a potential new target for amelioration of chemotherapy-induced cardiotoxicity.
Collapse
Affiliation(s)
- Kiran Das
- Centre of Biomedical Research, SGPGIMS Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India; Academy of Scientific and Innovative Research (AcSIR), India
| | - Madhuri Basak
- Centre of Biomedical Research, SGPGIMS Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Tarun Mahata
- Centre of Biomedical Research, SGPGIMS Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Manish Kumar
- Centre of Biomedical Research, SGPGIMS Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Dinesh Kumar
- Centre of Biomedical Research, SGPGIMS Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Sayan Biswas
- Forensic Medicine, College of Medicine and Sagore Dutta Hospital, B.T. Road, Kamarhati, Kolkata, West Bengal, 700058, India
| | | | | | | | - Kausik Mondal
- Zoology, University of Kalyani, Nadia, West Bengal, 741235, India
| | - Pranesh Kumar
- Pharmaceutical Sciences, Aryakul College of Pharmacy & Research, Natkur, Aryakul College Road, Lucknow, Uttar Pradesh, 226002, India
| | - Priyadip Das
- Chemistry, SRM Institute of Science and Technology, Kattankulathur, Tamilnadu, 603203, India
| | - Adele Stewart
- Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Biswanath Maity
- Centre of Biomedical Research, SGPGIMS Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India; Academy of Scientific and Innovative Research (AcSIR), India.
| |
Collapse
|
11
|
Wang Z, Chen J, Wang S, Sun Z, Lei Z, Zhang HT, Huang J. RGS6 suppresses TGF-β-induced epithelial-mesenchymal transition in non-small cell lung cancers via a novel mechanism dependent on its interaction with SMAD4. Cell Death Dis 2022; 13:656. [PMID: 35902557 PMCID: PMC9334288 DOI: 10.1038/s41419-022-05093-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 01/21/2023]
Abstract
Regulator of G-protein signaling 6 (RGS6) is a newly discovered tumor suppressor that has been shown to be protective in development of various cancers such as breast cancer and bladder cancer. But the mechanisms underlying these tumor-suppressing functions of RGS6 are not fully understood. Here, we discover a novel function of RGS6 in suppressing TGF-β-induced epithelial-mesenchymal transition (EMT) of non-small cell lung cancer (NSCLC) cells and in vivo NSCLC metastasis. Using both bioinformatics and experimental tools, we showed that RGS6 was downregulated in lung cancer tissues compared to noncancerous counterparts, and low expression of RGS6 was associated with poor survival of lung cancer patients. Overexpression of RGS6 suppressed TGF-β-induced EMT in vitro and TGF-β-promoted metastasis in vivo, by impairing gene expression of downstream effectors induced by the canonical TGF-β-SMAD signaling. The ability of RGS6 to suppress TGF-β-SMAD-mediated gene expression relied on its binding to SMAD4 to prevent complex formation between SMAD4 and SMAD2/3, but independent of its regulation of the G-protein signaling. Interaction between RGS6 and SMAD4 caused less nuclear entry of p-SMAD3 and SMAD4, resulting in inefficient SMAD3-mediated gene expression. Taken together, our findings reveal a novel and noncanonical role of RGS6 in regulation of TGF-β-induced EMT and metastasis of NSCLC and identify RGS6 as a prognostic marker and a potential novel target for NSCLC therapy.
Collapse
Affiliation(s)
- Zhao Wang
- grid.263761.70000 0001 0198 0694Soochow University Laboratory of Cancer Molecular Genetics, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,grid.263761.70000 0001 0198 0694Department of Genetics, School of Biology and Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China
| | - Jun Chen
- grid.263761.70000 0001 0198 0694Department of Thoracic Surgery, The First Affiliated Hospital of Soochow University, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215006 China
| | - Shengjie Wang
- grid.263761.70000 0001 0198 0694Soochow University Laboratory of Cancer Molecular Genetics, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,grid.263761.70000 0001 0198 0694Department of Genetics, School of Biology and Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,grid.89957.3a0000 0000 9255 8984Department of Basic Medicine, Kangda College of Nanjing Medical University, Lianyungang, 222000 China
| | - Zelong Sun
- grid.263761.70000 0001 0198 0694Soochow University Laboratory of Cancer Molecular Genetics, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,grid.263761.70000 0001 0198 0694Department of Genetics, School of Biology and Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China
| | - Zhe Lei
- grid.263761.70000 0001 0198 0694Soochow University Laboratory of Cancer Molecular Genetics, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,grid.263761.70000 0001 0198 0694Department of Genetics, School of Biology and Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,Suzhou Key Laboratory for Molecular Cancer Genetics, Suzhou, Jiangsu 215123 China
| | - Hong-Tao Zhang
- grid.263761.70000 0001 0198 0694Soochow University Laboratory of Cancer Molecular Genetics, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,grid.263761.70000 0001 0198 0694Department of Genetics, School of Biology and Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,Suzhou Key Laboratory for Molecular Cancer Genetics, Suzhou, Jiangsu 215123 China
| | - Jie Huang
- grid.263761.70000 0001 0198 0694Soochow University Laboratory of Cancer Molecular Genetics, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,grid.263761.70000 0001 0198 0694Department of Genetics, School of Biology and Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, Jiangsu 215123 China ,Suzhou Key Laboratory for Molecular Cancer Genetics, Suzhou, Jiangsu 215123 China
| |
Collapse
|
12
|
Sivagnanam S, Das K, Sivakadatcham V, Mahata T, Basak M, Pan I, Stewart A, Maity B, Das P. Generation of Self‐Assembled Structures Composed of Amphipathic, Charged Tripeptides for Intracellular Delivery of Pro‐Apoptotic Chemotherapeutics. Isr J Chem 2022. [DOI: 10.1002/ijch.202200001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Subramaniyam Sivagnanam
- Department of Chemistry SRM Institute of Science and Technology, SRM Nagar, Potheri University building, Room No 1210/8 Kattankulathur Tamil Nadu-603203 India
| | - Kiran Das
- Centre of Biomedical Research (CBMR) Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI) campus, Raebareli Road Lucknow Uttar Pradesh 226014 India
| | - Vijay Sivakadatcham
- Department of Chemistry SRM Institute of Science and Technology, SRM Nagar, Potheri University building, Room No 1210/8 Kattankulathur Tamil Nadu-603203 India
| | - Tarun Mahata
- Centre of Biomedical Research (CBMR) Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI) campus, Raebareli Road Lucknow Uttar Pradesh 226014 India
| | - Madhuri Basak
- Centre of Biomedical Research (CBMR) Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI) campus, Raebareli Road Lucknow Uttar Pradesh 226014 India
| | - Ieshita Pan
- Department of Biotechnology Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences Saveetha University Tamil Nadu 602105 India
| | - Adele Stewart
- Department of Biomedical Science Charles E. Schmidt College of Medicine Florida Atlantic University Jupiter FL 33458 USA
| | - Biswanath Maity
- Centre of Biomedical Research (CBMR) Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI) campus, Raebareli Road Lucknow Uttar Pradesh 226014 India
| | - Priyadip Das
- Department of Chemistry SRM Institute of Science and Technology, SRM Nagar, Potheri University building, Room No 1210/8 Kattankulathur Tamil Nadu-603203 India
| |
Collapse
|
13
|
RGS6 Drives Spinal Cord Injury by Inhibiting AMPK Pathway in Mice. DISEASE MARKERS 2022; 2022:4535652. [PMID: 35510037 PMCID: PMC9061016 DOI: 10.1155/2022/4535652] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 03/22/2022] [Indexed: 11/18/2022]
Abstract
Objective. Oxidative stress and inflammation play critical roles in the pathogenesis of spinal cord injury (SCI). Regulator of G protein signaling 6 (RGS6) is involved in controlling ROS generation and inflammatory response under different contexts. This study is aimed at investigating its role and underlying mechanism in SCI. Methods. Contusive SCI mouse models were generated, and lentiviral vectors were injected to silence or overexpress RGS6 in the spinal cord. To inhibit AMP-activated protein kinase (AMPK) activity, SCI mice were intraperitoneally injected with compound C (20 mg/kg) every two days. Oxidative and inflammatory markers were detected. Results. Spinal RGS6 expression was elevated upon SCI stimulation. RGS6 knockdown suppressed, while RGS6 overexpression aggravated oxidative stress, inflammation, and SCI in mice. Mechanistically, RGS6 elevation during SCI deactivated AMPK pathway, thereby exacerbating oxidative stress and inflammation in SCI mice. Conclusion. RGS6 is required for the initiation and progression of SCI, and knocking down RGS6 may provide promising therapeutic strategies for SCI patients.
Collapse
|
14
|
Sivagnanam S, Das K, Basak M, Mahata T, Stewart A, Maity B, Das P. Self-assembled dipeptide based fluorescent nanoparticles as a platform for developing cellular imaging probes and targeted drug delivery chaperones. NANOSCALE ADVANCES 2022; 4:1694-1706. [PMID: 36134376 PMCID: PMC9417502 DOI: 10.1039/d1na00885d] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/13/2022] [Indexed: 06/16/2023]
Abstract
Self-assembled peptide-based nanostructures, comprised of naturally occurring amino acids, display excellent biocompatibility, biodegradability, flexible responsiveness, and synthetic feasibility and can be customized for various biomedical applications. However, the lack of inherent optical properties of peptide-based nanoparticles is a limitation on their use as imaging probes or drug delivery vehicles. To overcome this impediment, we generated Boc protected tyrosine-tryptophan dipeptide-based nanoparticles (DPNPs) with structure rigidification by Zn(ii), which shifted the peptide's intrinsic fluorescent properties from the ultraviolet to the visible range. These DPNPs are photostable, biocompatible and have visible fluorescence signals that allow for real-time monitoring of their entry into cells. We further show that two DPNPs (PS1-Zn and PS2-Zn) can encapsulate the chemotherapeutic drug doxorubicin (Dox) and facilitate intracellular drug delivery resulting in cancer cell killing actions comparable to the unencapsulated drug. Finally, we chemically modified our DPNPs with an aptamer directed toward the epithelial cell surface marker EPCAM, which improved Dox delivery to the lung cancer epithelial cell line A549. In contrast, the aptamer conjugated DPNPs failed to deliver Dox into the cardiomyocyte cell line AC16. Theoretically, this strategy could be employed in vivo to specifically deliver Dox to cancer cells while sparing the myocardium, a major source of dose-limiting adverse events in the clinic. Our work represents an important proof-of-concept exercise demonstrating that ultra-short peptide-based fluorescent nanostructures have great promise for the development of new imaging probes and targeted drug delivery vehicles.
Collapse
Affiliation(s)
- Subramaniyam Sivagnanam
- Department of Chemistry, SRM Institute of Science and Technology SRM Nagar, Potheri, Kattankulathur Tamil Nadu 603203 India
| | - Kiran Das
- Centre of Biomedical Research, Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI) Campus Raebareli Road Lucknow Uttar Pradesh 226014 India
| | - Madhuri Basak
- Centre of Biomedical Research, Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI) Campus Raebareli Road Lucknow Uttar Pradesh 226014 India
| | - Tarun Mahata
- Centre of Biomedical Research, Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI) Campus Raebareli Road Lucknow Uttar Pradesh 226014 India
| | - Adele Stewart
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University Jupiter FL 33458 USA
| | - Biswanath Maity
- Centre of Biomedical Research, Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI) Campus Raebareli Road Lucknow Uttar Pradesh 226014 India
| | - Priyadip Das
- Department of Chemistry, SRM Institute of Science and Technology SRM Nagar, Potheri, Kattankulathur Tamil Nadu 603203 India
| |
Collapse
|
15
|
Sivagnanam S, Basak M, Kumar A, Das K, Mahata T, Rana P, Sengar AS, Ghosh S, Subramanian M, Stewart A, Maity B, Das P. Supramolecular Structures Generated via Self-Assembly of a Cell Penetrating Tetrapeptide Facilitate Intracellular Delivery of a Pro-apoptotic Chemotherapeutic Drug. ACS APPLIED BIO MATERIALS 2021; 4:6807-6820. [PMID: 35006981 DOI: 10.1021/acsabm.1c00530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Development of drug carriers, which can chaperone xenobiotics directly to their site of action, is an essential step for the advancement of precision medicine. Cationic nanoparticles can be used as a drug delivery platform for various agents including chemotherapeutics, oligonucleotides, and antibodies. Self-assembly of short peptides facilitates the formation of well-defined nanostructures suitable for drug delivery, and varying the polarity of the self-assembly medium changes the nature of noncovalent interactions in such a way as to generate numerous unique nanostructures. Here, we have synthesized an ultrashort cell-penetrating tetrapeptide (sequence Lys-Val-Ala-Val), with Lys as a cationic amino acid, and studied the self-assembly property of the BOC-protected (L1) and -deprotected (L2) analogues. Spherical assemblies obtained from L1/L2 in a 1:1 aqueous ethanol system have the ability to encapsulate small molecules and successfully enter into cells, thus representing them as potential candidates for intracellular drug delivery. To verify the efficacy of these peptides in the facilitation of drug efficacy, we generated encapsulated versions of the chemotherapeutic drug doxorubicin (Dox). L1- and L2-encapsulated Dox (Dox-L1 and Dox-L2), similar to the unencapsulated drug, induced upregulation of regulator of G protein signaling 6 (RGS6) and Gβ5, the critical mediators of ATM/p53-dependent apoptosis in Dox-treated cancer cells. Further, Dox-L1/L2 damaged DNA, triggered oxidative stress and mitochondrial dysfunction, compromised cell viability, and induced apoptosis. The ability of Dox-L1 to mediate cell death could be ameliorated via knockdown of either RGS6 or Gβ5, comparable to the results obtained with the unencapsulated drug. These data provide an important proof of principle, identifying L1/L2 as drug delivery matrices.
Collapse
Affiliation(s)
- Subramaniyam Sivagnanam
- Department of Chemistry, SRM Institute of Science and Technology, SRM Nagar, Potheri, Kattankulathur 603203, Tamil Nadu, India
| | - Madhuri Basak
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences (SGPGI) Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India
| | - Abilesh Kumar
- Department of Chemistry, SRM Institute of Science and Technology, SRM Nagar, Potheri, Kattankulathur 603203, Tamil Nadu, India
| | - Kiran Das
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences (SGPGI) Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India
| | - Tarun Mahata
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences (SGPGI) Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India
| | - Priya Rana
- Department of Chemistry, SRM Institute of Science and Technology, SRM Nagar, Potheri, Kattankulathur 603203, Tamil Nadu, India
| | - Abhishek Singh Sengar
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences (SGPGI) Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India
| | - Soumyajit Ghosh
- Department of Chemistry, SRM Institute of Science and Technology, SRM Nagar, Potheri, Kattankulathur 603203, Tamil Nadu, India
| | - Mahesh Subramanian
- Bio-Organic Division, Bhabha Atomic Research Centre (BARC), Anushaktinagar, Mumbai 400085, Maharashtra, India
| | - Adele Stewart
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, Florida 33458, United States
| | - Biswanath Maity
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences (SGPGI) Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India
| | - Priyadip Das
- Department of Chemistry, SRM Institute of Science and Technology, SRM Nagar, Potheri, Kattankulathur 603203, Tamil Nadu, India
| |
Collapse
|
16
|
Mahata T, Sengar AS, Basak M, Das K, Pramanick A, Verma SK, Singh PK, Biswas S, Sarkar S, Saha S, Chatterjee S, Das M, Stewart A, Maity B. Hepatic Regulator of G Protein Signaling 6 (RGS6) drives non-alcoholic fatty liver disease by promoting oxidative stress and ATM-dependent cell death. Redox Biol 2021; 46:102105. [PMID: 34534913 PMCID: PMC8446788 DOI: 10.1016/j.redox.2021.102105] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 08/14/2021] [Indexed: 12/15/2022] Open
Abstract
The pathophysiological mechanism(s) driving non-alcoholic fatty liver disease, the most prevalent chronic liver disease globally, have yet to be fully elucidated. Here, we identify regulator of G protein signaling 6 (RGS6), up-regulated in the livers of NAFLD patients, as a critical mediator of hepatic steatosis, fibrosis, inflammation, and cell death. Human patients with high hepatic RGS6 expression exhibited a corresponding high inflammatory burden, pronounced insulin resistance, and poor liver function. In mice, liver-specific RGS6 knockdown largely ameliorated high fat diet (HFD)-driven oxidative stress, fibrotic remodeling, inflammation, lipid deposition and cell death. RGS6 depletion allowed for maintenance of mitochondrial integrity restoring redox balance, improving fatty acid oxidation, and preventing loss of insulin receptor sensitivity in hepatocytes. RGS6 is both induced by ROS and increases ROS generation acting as a key amplification node to exacerbate oxidative stress. In liver, RGS6 forms a direct complex with ATM kinase supported by key aspartate residues in the RGS domain and is both necessary and sufficient to drive hyperlipidemia-dependent ATM phosphorylation. pATM and markers of DNA damage (γH2AX) were also elevated in livers from NAFLD patients particularly in samples with high RGS6 protein content. Unsurprisingly, RGS6 knockdown prevented ATM phosphorylation in livers from HFD-fed mice. Further, RGS6 mutants lacking the capacity for ATM binding fail to facilitate palmitic acid-dependent hepatocyte apoptosis underscoring the importance of the RGS6-ATM complex in hyperlipidemia-dependent cell death. Inhibition of RGS6, then, may provide a viable means to prevent or reverse liver damage by mitigating oxidative liver damage.
Collapse
Affiliation(s)
- Tarun Mahata
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Abhishek Singh Sengar
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Madhuri Basak
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Kiran Das
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Arnab Pramanick
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Sumit Kumar Verma
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India
| | - Praveen Kumar Singh
- Department of Surgery, Millers School of Medicine, University of Miami, Miami, FL, 33136, USA
| | - Sayan Biswas
- Department of Forensic Medicine, College of Medicine and Sagore Dutta Hospital, B.T. Road, Kamarhati, Kolkata, West Bengal, 700058, India
| | - Subhasish Sarkar
- Department of Surgery, College of Medicine and Sagore Dutta Hospital, B.T. Road, Kamarhati, Kolkata, West Bengal, 700058, India
| | - Sudipta Saha
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow, Uttar Pradesh, 226025, India
| | - Suvro Chatterjee
- Department of Biotechnology, Anna University and Vascular Biology Laboratory, AU-KBC Research Centre, MIT Campus, Chennai, 600044, India
| | - Madhusudan Das
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, West Bengal, 700019, India.
| | - Adele Stewart
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Biswanath Maity
- Centre of Biomedical Research, Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, Raebareli Road, Lucknow, Uttar Pradesh, 226014, India.
| |
Collapse
|
17
|
G protein β5-ATM complexes drive acetaminophen-induced hepatotoxicity. Redox Biol 2021; 43:101965. [PMID: 33933881 PMCID: PMC8105674 DOI: 10.1016/j.redox.2021.101965] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 12/14/2022] Open
Abstract
Excessive ingestion of the common analgesic acetaminophen (APAP) leads to severe hepatotoxicity. Here we identify G protein β5 (Gβ5), elevated in livers from APAP overdose patients, as a critical regulator of cell death pathways and autophagic signaling in APAP-exposed liver. Liver-specific knockdown of Gβ5 in mice protected the liver from APAP-dependent fibrosis, cell loss, oxidative stress, and inflammation following either acute or chronic APAP administration. Conversely, overexpression of Gβ5 in liver was sufficient to drive hepatocyte dysfunction and loss. In hepatocytes, Gβ5 depletion ameliorated mitochondrial dysfunction, allowed for maintenance of ATP generation and mitigated APAP-induced cell death. Further, Gβ5 knockdown also reversed impacts of APAP on kinase cascades (e.g. ATM/AMPK) signaling to mammalian target of rapamycin (mTOR), a master regulator of autophagy and, as a result, interrupted autophagic flux. Though canonically relegated to nuclear DNA repair pathways, ATM also functions in the cytoplasm to control cell death and autophagy. Indeed, we now show that Gβ5 forms a direct, stable complex with the FAT domain of ATM, important for autophosphorylation-dependent kinase activation. These data provide a viable explanation for these novel, G protein-independent actions of Gβ5 in liver. Thus, Gβ5 sits at a critical nexus in multiple pathological sequelae driving APAP-dependent liver damage.
Collapse
|
18
|
Ahlers-Dannen KE, Spicer MM, Fisher RA. RGS Proteins as Critical Regulators of Motor Function and Their Implications in Parkinson's Disease. Mol Pharmacol 2020; 98:730-738. [PMID: 32015009 DOI: 10.1124/mol.119.118836] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/25/2020] [Indexed: 11/22/2022] Open
Abstract
Parkinson disease (PD) is a devastating, largely nonfamilial, age-related disorder caused by the progressive loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). Release of DA from these neurons into the dorsal striatum is crucial for regulating movement and their loss causes PD. Unfortunately, the mechanisms underlying SNc neurodegeneration remain unclear, and currently there is no cure for PD, only symptomatic treatments. Recently, several regulator of G protein signaling (RGS) proteins have emerged as critical modulators of PD pathogenesis and/or motor dysfunction and dyskinesia: RGSs 4, 6, 9, and 10. Striatal RGS4 has been shown to exacerbate motor symptoms of DA loss by suppressing M4-autoreceptor-Gα i/o signaling in striatal cholinergic interneurons. RGS6 and RGS9 are key regulators of D2R-Gα i/o signaling in SNc DA neurons and striatal medium spiny neurons, respectively. RGS6, expressed in human and mouse SNc DA neurons, suppresses characteristic PD hallmarks in aged mice, including SNc DA neuron loss, motor deficits, and α-synuclein accumulation. After DA depletion, RGS9 (through its inhibition of medium spiny neuron D2R signaling) suppresses motor dysfunction induced by L-DOPA or D2R-selective agonists. RGS10 is highly expressed in microglia, the brain's resident immune cells. Within the SNc, RGS10 may promote DA neuron survival through the upregulation of prosurvival genes and inhibition of microglial inflammatory factor expression. Thus, RGSs 4, 6, 9, and 10 are critical modulators of cell signaling pathways that promote SNc DA neuron survival and/or proper motor control. Accordingly, these RGS proteins represent novel therapeutic targets for the treatment of PD pathology. SIGNIFICANCE STATEMENT: Parkinson disease (PD), the most common movement disorder, is a progressive neurodegenerative disease characterized by substantia nigra pars compacta (SNc) dopamine (DA) neuron loss and subsequent motor deficits. Current PD therapies only target disease motor symptomology and are fraught with side effects. Therefore, researchers have begun to explore alternative therapeutic options. Regulator of G protein signaling (RGS) proteins, whether primarily expressed in SNc DA neurons (RGS6), striatal neurons (RGSs 4 and 9), or microglia (RGS10), modulate key signaling pathways important for SNc DA neuron survival and/or proper motor control. As such, RGS proteins represent novel therapeutic targets in PD.
Collapse
Affiliation(s)
- Katelin E Ahlers-Dannen
- Department of Neuroscience and Pharmacology (K.E.A.-D., M.M.S., R.A.F.), Iowa Neuroscience Institute (R.A.F.), and Interdisciplinary Graduate Program in Molecular Medicine (M.M.S., R.A.F.), University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Mackenzie M Spicer
- Department of Neuroscience and Pharmacology (K.E.A.-D., M.M.S., R.A.F.), Iowa Neuroscience Institute (R.A.F.), and Interdisciplinary Graduate Program in Molecular Medicine (M.M.S., R.A.F.), University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Rory A Fisher
- Department of Neuroscience and Pharmacology (K.E.A.-D., M.M.S., R.A.F.), Iowa Neuroscience Institute (R.A.F.), and Interdisciplinary Graduate Program in Molecular Medicine (M.M.S., R.A.F.), University of Iowa Carver College of Medicine, Iowa City, Iowa
| |
Collapse
|
19
|
Huang Z, Shu J, Jiang W, Jiang M, Lu Y, Dai H, Xu N, Yuan H, Cai J. Regulator of G Protein Signaling 6 Facilities Cardiac Hypertrophy by Activating Apoptosis Signal-Regulating Kinase 1-P38/c-JUN N-Terminal Kinase 1/2 Signaling. J Am Heart Assoc 2019; 7:e009179. [PMID: 30371330 PMCID: PMC6404897 DOI: 10.1161/jaha.118.009179] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background Regulator of G protein signaling 6 (RGS6) is an important member of the RGS family and produces pleiotropic regulatory effects on cardiac pathophysiology. However, the role of RGS6 protein in cardiomyocytes during angiotensin II– and pressure overload–induced cardiac hypertrophy remain unknown. Methods and Results Here, we used a genetic approach to study the regulatory role of RGS6 in cardiomyocytes during pathological cardiac hypertrophy. RGS6 expression was significantly increased in failing human hearts and in hypertrophic murine hearts. The extent of aortic banding–induced cardiac hypertrophy, dysfunction, and fibrosis in cardiac‐specific RGS6 knockout mice was alleviated, whereas the hearts of transgenic mice with cardiac‐specific RGS6 overexpression exhibited exacerbated responses to pressure overload. Consistent with these findings, RGS6 also facilitated an angiotensin II–induced hypertrophic response in isolated cardiomyocytes. According to the mechanistic studies, RGS6 mediated cardiac hypertrophy by directly interacting with apoptosis signal–regulating kinase 1, which further activates the P38‐c‐JUN N‐terminal kinase 1/2 signaling pathway. Conclusions Based on our findings, RGS6 aggravates cardiac hypertrophy, and the RGS6‐apoptosis signal–regulating kinase 1 pathway represents a potential therapeutic target to attenuate pressure overload–driven cardiac remodeling.
Collapse
Affiliation(s)
- Zhijun Huang
- 2 The Center of Clinical Pharmacology The Third Xiangya Hospital Central South University Changsha China
| | - Jingxian Shu
- 2 The Center of Clinical Pharmacology The Third Xiangya Hospital Central South University Changsha China
| | - Weihong Jiang
- 1 Department of Cardiology The Third Xiangya Hospital Central South University Changsha China
| | - Mengqing Jiang
- 1 Department of Cardiology The Third Xiangya Hospital Central South University Changsha China
| | - Yao Lu
- 2 The Center of Clinical Pharmacology The Third Xiangya Hospital Central South University Changsha China
| | - Haijiang Dai
- 1 Department of Cardiology The Third Xiangya Hospital Central South University Changsha China
| | - Nana Xu
- 2 The Center of Clinical Pharmacology The Third Xiangya Hospital Central South University Changsha China
| | - Hong Yuan
- 2 The Center of Clinical Pharmacology The Third Xiangya Hospital Central South University Changsha China
| | - Jingjing Cai
- 1 Department of Cardiology The Third Xiangya Hospital Central South University Changsha China.,2 The Center of Clinical Pharmacology The Third Xiangya Hospital Central South University Changsha China
| |
Collapse
|
20
|
O'Brien JB, Wilkinson JC, Roman DL. Regulator of G-protein signaling (RGS) proteins as drug targets: Progress and future potentials. J Biol Chem 2019; 294:18571-18585. [PMID: 31636120 DOI: 10.1074/jbc.rev119.007060] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) play critical roles in regulating processes such as cellular homeostasis, responses to stimuli, and cell signaling. Accordingly, GPCRs have long served as extraordinarily successful drug targets. It is therefore not surprising that the discovery in the mid-1990s of a family of proteins that regulate processes downstream of GPCRs generated great excitement in the field. This finding enhanced the understanding of these critical signaling pathways and provided potentially new targets for pharmacological intervention. These regulators of G-protein signaling (RGS) proteins were viewed by many as nodes downstream of GPCRs that could be targeted with small molecules to tune signaling processes. In this review, we provide a brief overview of the discovery of RGS proteins and of the gradual and continuing discovery of their roles in disease states, focusing particularly on cancer and neurological disorders. We also discuss high-throughput screening efforts that have led to the discovery first of peptide-based and then of small-molecule inhibitors targeting a subset of the RGS proteins. We explore the unique mechanisms of RGS inhibition these chemical tools have revealed and highlight the most up-to-date studies using these tools in animal experiments. Finally, we discuss the future opportunities in the field, as there are clearly more avenues left to be explored and potentials to be realized.
Collapse
Affiliation(s)
- Joseph B O'Brien
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242
| | - Joshua C Wilkinson
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242
| | - David L Roman
- Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, Iowa City, Iowa 52242; Iowa Neuroscience Institute, Iowa City, Iowa 52242; Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242.
| |
Collapse
|
21
|
Squires KE, Montañez-Miranda C, Pandya RR, Torres MP, Hepler JR. Genetic Analysis of Rare Human Variants of Regulators of G Protein Signaling Proteins and Their Role in Human Physiology and Disease. Pharmacol Rev 2018; 70:446-474. [PMID: 29871944 DOI: 10.1124/pr.117.015354] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins modulate the physiologic actions of many neurotransmitters, hormones, and other signaling molecules. Human RGS proteins comprise a family of 20 canonical proteins that bind directly to G protein-coupled receptors/G protein complexes to limit the lifetime of their signaling events, which regulate all aspects of cell and organ physiology. Genetic variations account for diverse human traits and individual predispositions to disease. RGS proteins contribute to many complex polygenic human traits and pathologies such as hypertension, atherosclerosis, schizophrenia, depression, addiction, cancers, and many others. Recent analysis indicates that most human diseases are due to extremely rare genetic variants. In this study, we summarize physiologic roles for RGS proteins and links to human diseases/traits and report rare variants found within each human RGS protein exome sequence derived from global population studies. Each RGS sequence is analyzed using recently described bioinformatics and proteomic tools for measures of missense tolerance ratio paired with combined annotation-dependent depletion scores, and protein post-translational modification (PTM) alignment cluster analysis. We highlight selected variants within the well-studied RGS domain that likely disrupt RGS protein functions and provide comprehensive variant and PTM data for each RGS protein for future study. We propose that rare variants in functionally sensitive regions of RGS proteins confer profound change-of-function phenotypes that may contribute, in newly appreciated ways, to complex human diseases and/or traits. This information provides investigators with a valuable database to explore variation in RGS protein function, and for targeting RGS proteins as future therapeutic targets.
Collapse
Affiliation(s)
- Katherine E Squires
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Carolina Montañez-Miranda
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Rushika R Pandya
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Matthew P Torres
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - John R Hepler
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| |
Collapse
|
22
|
Chakraborti S, Pramanick A, Saha S, Roy SS, Chaudhuri AR, Das M, Ghosh S, Stewart A, Maity B. Atypical G Protein β5 Promotes Cardiac Oxidative Stress, Apoptosis, and Fibrotic Remodeling in Response to Multiple Cancer Chemotherapeutics. Cancer Res 2017; 78:528-541. [DOI: 10.1158/0008-5472.can-17-1280] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 09/08/2017] [Accepted: 11/13/2017] [Indexed: 11/16/2022]
|
23
|
Chakravarti B, Yang J, Ahlers-Dannen KE, Luo Z, Flaherty HA, Meyerholz DK, Anderson ME, Fisher RA. Essentiality of Regulator of G Protein Signaling 6 and Oxidized Ca 2+/Calmodulin-Dependent Protein Kinase II in Notch Signaling and Cardiovascular Development. J Am Heart Assoc 2017; 6:JAHA.117.007038. [PMID: 29079565 PMCID: PMC5721783 DOI: 10.1161/jaha.117.007038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background Congenital heart defects are the most common birth defects worldwide. Although defective Notch signaling is the major cause of mouse embryonic death from cardiovascular defects, how Notch signaling is regulated during embryonic vasculogenesis and heart development is poorly understood. Methods and Results Regulator of G protein signaling 6 (RGS6)−/−/Ca2+/calmodulin‐dependent protein kinase II (CaMKII)VV double mutant mice were developed by crossing RGS6−/− mice with mice expressing an oxidation‐resistant CaMKIIδ (CaMKIIVV), and the resulting embryonic defects/lethality were investigated using E7.5 to E15.5 embryos. While loss of either RGS6 or oxidized CaMKIIδ does not alter embryogenesis, their combined loss causes defective Notch signaling, severe cardiovascular defects, and embryonic lethality (≈E10.5–11.5). Embryos lacking RGS6 and expressing oxidation‐resistant CaMKIIδ exhibit reduced myocardial wall thickness, abnormal trabeculation, and arterial specification defects. Double mutants show vascular remodeling defects, including reduced neurovascularization, delayed neural tube maturation, and small dorsal aortae. These striking cardiovascular defects were accompanied by placental and yolk sac defects in angiogenesis, hematopoiesis, and vascular remodeling similar to what is seen with defective Notch1 signaling. Double mutant hearts, embryos, and yolk sacs exhibit profound downregulation of Notch1, Jagged 1, and Notch downstream target genes Hey1, Hey2, and Hey1L as well as impaired Notch1 signaling in embryos/hearts. Conclusions RGS6 and oxidized CaMKIIδ together function as novel critical upstream modulators of Notch signaling required for normal cardiovascular development and embryo survival. Their combined need indicates that they function in parallel pathways needed for Notch1 signaling in yolk sac, placenta and embryos. Thus, dysregulated embryonic RGS6 expression and oxidative activation of CaMKII may potentially contribute to congenital heart defects.
Collapse
Affiliation(s)
- Bandana Chakravarti
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA
| | - Jianqi Yang
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA
| | | | - Zili Luo
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA
| | | | - David K Meyerholz
- Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, IA
| | - Mark E Anderson
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Rory A Fisher
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA
| |
Collapse
|
24
|
Alqinyah M, Hooks SB. Regulating the regulators: Epigenetic, transcriptional, and post-translational regulation of RGS proteins. Cell Signal 2017; 42:77-87. [PMID: 29042285 DOI: 10.1016/j.cellsig.2017.10.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/06/2017] [Accepted: 10/13/2017] [Indexed: 12/11/2022]
Abstract
Regulators of G protein signaling (RGS) are a family of proteins classically known to accelerate the intrinsic GTPase activity of G proteins, which results in accelerated inactivation of heterotrimeric G proteins and inhibition of G protein coupled receptor signaling. RGS proteins play major roles in essential cellular processes, and dysregulation of RGS protein expression is implicated in multiple diseases, including cancer, cardiovascular and neurodegenerative diseases. The expression of RGS proteins is highly dynamic and is regulated by epigenetic, transcriptional and post-translational mechanisms. This review summarizes studies that report dysregulation of RGS protein expression in disease states, and presents examples of drugs that regulate RGS protein expression. Additionally, this review discusses, in detail, the transcriptional and post-transcriptional mechanisms regulating RGS protein expression, and further assesses the therapeutic potential of targeting these mechanisms. Understanding the molecular mechanisms controlling the expression of RGS proteins is essential for the development of therapeutics that indirectly modulate G protein signaling by regulating expression of RGS proteins.
Collapse
Affiliation(s)
- Mohammed Alqinyah
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA
| | - Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA.
| |
Collapse
|
25
|
Sjögren B. The evolution of regulators of G protein signalling proteins as drug targets - 20 years in the making: IUPHAR Review 21. Br J Pharmacol 2017; 174:427-437. [PMID: 28098342 DOI: 10.1111/bph.13716] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 12/11/2016] [Accepted: 01/08/2017] [Indexed: 12/11/2022] Open
Abstract
Regulators of G protein signalling (RGS) proteins are celebrating the 20th anniversary of their discovery. The unveiling of this new family of negative regulators of G protein signalling in the mid-1990s solved a persistent conundrum in the G protein signalling field, in which the rate of deactivation of signalling cascades in vivo could not be replicated in exogenous systems. Since then, there has been tremendous advancement in the knowledge of RGS protein structure, function, regulation and their role as novel drug targets. RGS proteins play an important modulatory role through their GTPase-activating protein (GAP) activity at active, GTP-bound Gα subunits of heterotrimeric G proteins. They also possess many non-canonical functions not related to G protein signalling. Here, an update on the status of RGS proteins as drug targets is provided, highlighting advances that have led to the inclusion of RGS proteins in the IUPHAR/BPS Guide to PHARMACOLOGY database of drug targets.
Collapse
Affiliation(s)
- B Sjögren
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
26
|
Development of a bimolecular luminescence complementation assay for RGS: G protein interactions in cells. Anal Biochem 2017; 522:10-17. [PMID: 28115169 DOI: 10.1016/j.ab.2017.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 01/10/2017] [Accepted: 01/18/2017] [Indexed: 02/03/2023]
Abstract
Cell based assessment tools and screening platforms are the preferred paradigm for small molecule identification and validation due to selectively identifying molecules with cellular activity and validation of compound activity against target proteins in their native environment. With respect to Regulator of G Protein Signaling (RGS) proteins, current cell based methodologies are either low throughput or monitor downstream signaling consequences. The increasing number of reports indicating RGS function in various disease pathogeneses highlights the need for a robust RGS inhibitor discovery and characterization paradigm. Promega's NanoBit Protein Complementation Assay utilizes NanoLuc, an engineered luciferase with enhanced luminescence characteristics which allow for both robust and kinetic assessment of protein interaction formation and disruption. Here we characterized 15 separate RGS: G protein interactions using this system. The binding profile of RGS: Gα interactions correlates to prior published biochemical binding profiles of these proteins. Additionally, we demonstrated this system is suitable for high throughput screening efforts via calculation of Z-factors for three of the interactions and demonstrated that a known small molecule inhibitor of RGS4 disrupts the RGS4: Gαi1 protein-protein interaction. In conclusion, the NanoBit Protein Complementation Assay holds promise as a robust platform for discovery and characterization of RGS inhibitors.
Collapse
|
27
|
Transcriptome modifications in human gingival fibroblasts exposed to 2-hydroxyethyl methacrylate. Gene 2016; 582:38-46. [PMID: 26828614 DOI: 10.1016/j.gene.2016.01.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/26/2016] [Accepted: 01/27/2016] [Indexed: 02/08/2023]
Abstract
2-Hydroxyethyl methacrylate (HEMA),a tooth filling material, was proven to have toxic effects on different cell types, including human gingival fibroblasts (HGFs), and to be able to influence odontoblast vitality. The aim of the present study was to assess the differential transcriptome modulation induced by low HEMA concentration in cultured HGFs. RNA extracted from cultured HGFs exposed to 3 mmol/l HEMA for 24 or 96 h underwent a whole genome microarray analysis. Data analysis showed the presence of two gene clusters, composed by 310 transcripts differentially expressed after 24- and 96-h HEMA treatment compared to controls. Functional analysis demonstrated that these transcripts are mainly involved in cellular survival and death, and inflammatory response. The study highlighted an overall damage induced by HEMA exposure at both 24 and 96 h, mainly leading to a proliferation impairment. Interestingly, 24-h HEMA treatment seems to induce the cells to trigger repair mechanisms, evidencing an early compensatory response, whereas 96-h incubation appears to cause the occurrence of apoptosis as a consequence of the chronic damage.
Collapse
|
28
|
Ahlers KE, Chakravarti B, Fisher RA. RGS6 as a Novel Therapeutic Target in CNS Diseases and Cancer. AAPS JOURNAL 2016; 18:560-72. [PMID: 27002730 DOI: 10.1208/s12248-016-9899-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/25/2016] [Indexed: 12/17/2022]
Abstract
Regulator of G protein signaling (RGS) proteins are gatekeepers regulating the cellular responses induced by G protein-coupled receptor (GPCR)-mediated activation of heterotrimeric G proteins. Specifically, RGS proteins determine the magnitude and duration of GPCR signaling by acting as a GTPase-activating protein for Gα subunits, an activity facilitated by their semiconserved RGS domain. The R7 subfamily of RGS proteins is distinguished by two unique domains, DEP/DHEX and GGL, which mediate membrane targeting and stability of these proteins. RGS6, a member of the R7 subfamily, has been shown to specifically modulate Gαi/o protein activity which is critically important in the central nervous system (CNS) for neuronal responses to a wide array of neurotransmitters. As such, RGS6 has been implicated in several CNS pathologies associated with altered neurotransmission, including the following: alcoholism, anxiety/depression, and Parkinson's disease. In addition, unlike other members of the R7 subfamily, RGS6 has been shown to regulate G protein-independent signaling mechanisms which appear to promote both apoptotic and growth-suppressive pathways that are important in its tumor suppressor function in breast and possibly other tissues. Further highlighting the importance of RGS6 as a target in cancer, RGS6 mediates the chemotherapeutic actions of doxorubicin and blocks reticular activating system (Ras)-induced cellular transformation by promoting degradation of DNA (cytosine-5)-methyltransferase 1 (DNMT1) to prevent its silencing of pro-apoptotic and tumor suppressor genes. Together, these findings demonstrate the critical role of RGS6 in regulating both G protein-dependent CNS pathology and G protein-independent cancer pathology implicating RGS6 as a novel therapeutic target.
Collapse
Affiliation(s)
- Katelin E Ahlers
- Department of Pharmacology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 2-505 Bowen Science Building, Iowa City, Iowa, 52242, USA
| | - Bandana Chakravarti
- Department of Pharmacology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 2-505 Bowen Science Building, Iowa City, Iowa, 52242, USA
| | - Rory A Fisher
- Department of Pharmacology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 2-505 Bowen Science Building, Iowa City, Iowa, 52242, USA. .,Department of Internal Medicine, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, 52242, USA.
| |
Collapse
|
29
|
Luo Y, Qin SL, Yu MH, Mu YF, Wang ZS, Zhong M. Prognostic value of regulator of G-protein signaling 6 in colorectal cancer. Biomed Pharmacother 2015; 76:147-52. [DOI: 10.1016/j.biopha.2015.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022] Open
|
30
|
Lyu JH, Park DW, Huang B, Kang SH, Lee SJ, Lee C, Bae YS, Lee JG, Baek SH. RGS2 suppresses breast cancer cell growth via a MCPIP1-dependent pathway. J Cell Biochem 2015; 116:260-7. [PMID: 25187114 DOI: 10.1002/jcb.24964] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/29/2014] [Indexed: 01/22/2023]
Abstract
Regulator of G protein signaling 2 (RGS2) is a member of a family of proteins that functions as a GTPase-activating protein (GAP) for Gα subunits. RGS2 mRNA expression is lower in breast cancerous tissues than in normal tissues. In addition, expression of RGS2 is also lower in MCF7 (cancerous breast cells) than in MCF10A (normal breast cells). Here we investigated whether RGS2 inhibits growth of breast cancer cells. RGS2 overexpression in MCF7 cells inhibited epidermal growth factor- or serum-induced proliferation. In HEK293T cells expressing RGS2, cell growth was also significantly suppressed (In addition, exogenous expression of RGS2 in HEK293T cells resulted in the significant suppression of cell growth). These results suggest that RGS2 may have a tumor suppressor function. MG-132 treatment of MCF7 cells increased endogenous or exogenous RGS2 levels, suggesting a post-transcriptional regulatory mechanism that controls RGS2 protein levels. RGS2 protein was degraded polyubiquitinated the K71 residue, but stabilized by deubiquitinase monocyte chemotactic protein-induced protein 1 (MCPIP1), and not affected by dominant negative mutant (C157A) of MCPIP1. Gene expression profiling study showed that overexpression of RGS2 decreased levels of testis specific Y encoded like protein 5 (TSPYL5), which plays a causal role in breast oncogenesis. TSPYL5 protein expression was low in MCF10A and high in MCF7 cells, showing the opposite aspect to RGS2 expression. Additionally, RGS2 or MCPIP1 overexpression in MCF7 cells decreased TSPYL5 protein level, indicating that RGS2 stabilized by MCPIP1 have diminished TSPYL5 protein levels, thereby exerting an inhibitory effect of breast cancer cell growth.
Collapse
Affiliation(s)
- Ji Hyo Lyu
- Department of Biochemistry and Molecular Biology, Aging-Associated Vascular Disease Research Center, Daegu, 705-802, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Xu Z, Zuo Y, Wang J, Yu Z, Peng F, Chen Y, Dong Y, Hu X, Zhou Q, Ma H, Bao Y, Chen M. Overexpression of the regulator of G-protein signaling 5 reduces the survival rate and enhances the radiation response of human lung cancer cells. Oncol Rep 2015; 33:2899-907. [PMID: 25891540 DOI: 10.3892/or.2015.3917] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/13/2015] [Indexed: 11/05/2022] Open
Abstract
Regulator of G protein signaling 5 (RGS5) belongs to the R4 subfamily of RGS proteins, a family of GTPase activating proteins, which is dynamically regulated in various biological processes including blood pressure regulation, smooth muscle cell pathology, fat metabolism and tumor angiogenesis. Low-expression of RGS5 was reported to be associated with tumor progression in lung cancer. In the present study, we examined the potential roles of RGS5 in human lung cancer cells by overexpressing RGS5 in the cancer cells and further explored the underlying molecular mechanisms. The RGS5 gene was cloned and transfected into the human lung cancer cell lines A549 and Calu-3. The cells were tested for apoptosis with flow cytometry, for viability with MTT, for mobility and adhesion capacity. The radiosensitization effect of RGS5 was measured by a colony formation assay. The mechanisms of RGS5 functioning was also investigated by detection of protein expression with western blot analysis, including PARP, caspase 3 and 9, bax, bcl2, Rock1, Rock2, CDC42, phospho-p53 (Serine 15) and p53. The present study demonstrated that RGS5 overexpression remarkably induced apoptosis in human lung cancer cells, which was suggested to be through mitochondrial mechanisms. Overexpression of RGS5 resulted in significantly lower adhesion and migration abilities of the lung cancer cells (P<0.01). Furthermore, overexpression of RGS5 sensitized the lung cancer cells to radiation. In conclusion, the present study showed that RGS5 played an inhibitory role in human lung cancer cells through induction of apoptosis. Furthermore, RGS5 enhanced the cytotoxic effect of radiation in the human lung cancer cells. Our results indicated that RGS5 may be a potential target for cancer therapy.
Collapse
Affiliation(s)
- Zumin Xu
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, P.R. China
| | - Yufang Zuo
- Cancer Center, Affiliated Hospital of Guangdong Medical College, Zhanjiang, Guangdong 524000, P.R. China
| | - Jin Wang
- Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310012, P.R. China
| | - Zhonghua Yu
- Cancer Center, Affiliated Hospital of Guangdong Medical College, Zhanjiang, Guangdong 524000, P.R. China
| | - Fang Peng
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, P.R. China
| | - Yuanyuan Chen
- Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310012, P.R. China
| | - Yong Dong
- Cancer Center, Shilong People's Hospital, Dongguan City, Guangdong 523321, P.R. China
| | - Xiao Hu
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, P.R. China
| | - Qichao Zhou
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, P.R. China
| | - Honglian Ma
- Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310012, P.R. China
| | - Yong Bao
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, P.R. China
| | - Ming Chen
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060, P.R. China
| |
Collapse
|
32
|
Stewart A, Maity B, Fisher RA. Two for the Price of One: G Protein-Dependent and -Independent Functions of RGS6 In Vivo. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 133:123-51. [PMID: 26123305 DOI: 10.1016/bs.pmbts.2015.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Regulator of G protein signaling 6 (RGS6) is unique among the members of the RGS protein family as it remains the only protein with the demonstrated capacity to control G protein-dependent and -independent signaling cascades in vivo. RGS6 inhibits signaling mediated by γ-aminobutyric acid B receptors, serotonin 1A receptors, μ opioid receptors, and muscarinic acetylcholine 2 receptors. RGS6 deletion triggers distinct behavioral phenotypes resulting from potentiated signaling by these G protein-coupled receptors namely ataxia, a reduction in anxiety and depression, enhanced analgesia, and increased parasympathetic tone, respectively. In addition, RGS6 possesses potent proapoptotic and growth suppressive actions. In heart, RGS6-dependent reactive oxygen species (ROS) production promotes doxorubicin (Dox)-induced cardiomyopathy, while in cancer cells RGS6/ROS signaling is necessary for activation of the ataxia telangiectasia mutated/p53/apoptosis pathway required for the chemotherapeutic efficacy of Dox. Further, by facilitating Tip60 (trans-acting regulator protein of HIV type 1-interacting protein 60 kDa)-dependent DNA methyltransferase 1 degradation, RGS6 suppresses cellular transformation in response to oncogenic Ras. The culmination of these G protein-independent actions results in potent tumor suppressor actions of RGS6 in the murine mammary epithelium. This work summarizes evidence from human genetic studies and model animals implicating RGS6 in normal physiology, disease, and the pharmacological actions of multiple drugs. Though efforts by multiple laboratories have contributed to the ever-growing RGS6 oeuvre, the pleiotropic nature of this gene will likely lead to additional work detailing the importance of RGS6 in neuropsychiatric disorders, cardiovascular disease, and cancer.
Collapse
Affiliation(s)
- Adele Stewart
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Biswanath Maity
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Rory A Fisher
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
| |
Collapse
|
33
|
Regulator of G-protein signaling 6 (RGS6) in cardiology and oncology. Int J Cardiol 2015; 187:99-102. [PMID: 25828322 DOI: 10.1016/j.ijcard.2015.03.278] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 03/19/2015] [Indexed: 02/06/2023]
|
34
|
Regulator of G protein signaling 6 is a critical mediator of both reward-related behavioral and pathological responses to alcohol. Proc Natl Acad Sci U S A 2015; 112:E786-95. [PMID: 25646431 DOI: 10.1073/pnas.1418795112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Alcohol is the most commonly abused drug worldwide, and chronic alcohol consumption is a major etiological factor in the development of multiple pathological sequelae, including alcoholic cardiomyopathy and hepatic cirrhosis. Here, we identify regulator of G protein signaling 6 (RGS6) as a critical regulator of both alcohol-seeking behaviors and the associated cardiac and hepatic morbidities through two mechanistically divergent signaling actions. RGS6(-/-) mice consume less alcohol when given free access and are less susceptible to alcohol-induced reward and withdrawal. Antagonism of GABA(B) receptors or dopamine D2 receptors partially reversed the reduction in alcohol consumption in RGS6(-/-) animals. Strikingly, dopamine transporter inhibition completely restored alcohol seeking in mice lacking RGS6. RGS6 deficiency was associated with alterations in the expression of genes controlling dopamine (DA) homeostasis and a reduction in DA levels in the striatum. Taken together, these data implicate RGS6 as an essential regulator of DA bioavailability. RGS6 deficiency also provided dramatic protection against cardiac hypertrophy and fibrosis, hepatic steatosis, and gastrointestinal barrier dysfunction and endotoxemia when mice were forced to consume alcohol. Although RGS proteins canonically function as G-protein regulators, RGS6-dependent, alcohol-mediated toxicity in the heart, liver, and gastrointestinal tract involves the ability of RGS6 to promote reactive oxygen species-dependent apoptosis, an action independent of its G-protein regulatory capacity. We propose that inhibition of RGS6 might represent a viable means to reduce alcohol cravings and withdrawal in human patients, while simultaneously protecting the heart and liver from further damage upon relapse.
Collapse
|
35
|
Rgs6 is required for adult maintenance of dopaminergic neurons in the ventral substantia nigra. PLoS Genet 2014; 10:e1004863. [PMID: 25501001 PMCID: PMC4263397 DOI: 10.1371/journal.pgen.1004863] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/29/2014] [Indexed: 12/03/2022] Open
Abstract
Parkinson disease (PD) is characterized by the preferential, but poorly understood, vulnerability to degeneration of midbrain dopaminergic (mDA) neurons in the ventral substantia nigra compacta (vSNc). These sensitive mDA neurons express Pitx3, a transcription factor that is critical for their survival during development. We used this dependence to identify, by flow cytometry and expression profiling, the negative regulator of G-protein signaling Rgs6 for its restricted expression in these neurons. In contrast to Pitx3−/− mDA neurons that die during fetal (vSNc) or post-natal (VTA) period, the vSNc mDA neurons of Rgs6−/− mutant mice begin to exhibit unilateral signs of degeneration at around 6 months of age, and by one year cell loss is observed in a fraction of mice. Unilateral cell loss is accompanied by contralateral degenerating neurons that exhibit smaller cell size, altered morphology and reduced dendritic network. The degenerating neurons have low levels of tyrosine hydroxylase (TH) and decreased nuclear Pitx3; accordingly, expression of many Pitx3 target gene products is altered, including Vmat2, Bdnf, Aldh1a1 (Adh2) and Fgf10. These low TH neurons also express markers of increased dopamine signaling, namely increased DAT and phospho-Erk1/2 expression. The late onset degeneration may reflect the protective action of Rgs6 against excessive DA signaling throughout life. Rgs6-dependent protection is thus critical for adult survival and maintenance of the vSNc mDA neurons that are most affected in PD. The locomotor deficits associated with Parkinson disease result from the death of a specific subset of dopamine neurons in the ventral part of the midbrain. The reason for the greater sensitivity to degeneration of those, relative to other, neurons is not clear. Prior work showed that the Pitx3 transcription factor is specifically expressed in these neurons where it has a survival role during development. The present work identified a cell signaling component, Rgs6, that is also restricted to the sensitive neurons in the midbrain and that exerts a protective function, particularly late in life. While the loss of Rgs6 function may predispose or contribute to Parkinson disease, its stimulation may provide a novel therapeutic avenue to treat Parkinson disease.
Collapse
|
36
|
Ishaq M, Khan MA, Sharma K, Sharma G, Dutta RK, Majumdar S. Gambogic acid induced oxidative stress dependent caspase activation regulates both apoptosis and autophagy by targeting various key molecules (NF-κB, Beclin-1, p62 and NBR1) in human bladder cancer cells. Biochim Biophys Acta Gen Subj 2014; 1840:3374-84. [PMID: 25218692 DOI: 10.1016/j.bbagen.2014.08.019] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/22/2014] [Accepted: 08/26/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Gambogic acid is a potent anticancer agent and has been found effective against various types of cancer cells. The present study was addressed to explore the cytotoxic potential of Gambogic acid and the modulation of autophagy and apoptosis in bladder cancer cells T24 and UMUC3. METHODS Bladder cancer cell lines T24 and UMUC3 were treated with Gambogic acid, apoptosis was checked by flow-cytometry and expression of various autophagy and apoptosis related proteins was monitored by Western blotting. Confocal microscope was used for colocalization of p62 and Beclin-1. RESULTS Gambogic acid induces reactive oxygen species, and elicits a strong autophagic response by activating JNK at earlier time points, which is inhibited at later time points with the activation of caspases. Reactive oxygen species mediated caspase activation causes degradation of autophagic proteins, cleavage of molecular chaperones (Hsp90 and GRP-78) and adaptor proteins (p62 and NBR1). Gambogic acid treatment results in mitochondrial hyperpolarization and cytochrome c release and activates caspases involved in both extrinsic and intrinsic apoptotic pathways. Gambogic acid abrogates NF-κB activation by ROS mediated inhibition of IκB-α phosphorylation. Functionally Gambogic acid induced autophagy acts as a strong cell survival response and delays caspase activation. CONCLUSION Our study provides the new insights about the mechanism of Gambogic acid induced modulation of autophagy and apoptosis in bladder cancer cells. All the molecular events responsible for Gambogic acid induced autophagy and apoptosis are mediated by reactive oxygen species. GENERAL SIGNIFICANCE Since Gambogic acid targets various cell survival molecules therefore, it may be considered as a potential anticancer agent against bladder cancer.
Collapse
Affiliation(s)
- Mohammad Ishaq
- Division of Cell Biology and Immunology, CSIR-Institute of Microbial Technology, Chandigarh 160 036, India
| | - Mohammad Aslam Khan
- Division of Cell Biology and Immunology, CSIR-Institute of Microbial Technology, Chandigarh 160 036, India
| | - Kapil Sharma
- Division of Cell Biology and Immunology, CSIR-Institute of Microbial Technology, Chandigarh 160 036, India
| | - Gaurav Sharma
- Division of Cell Biology and Immunology, CSIR-Institute of Microbial Technology, Chandigarh 160 036, India
| | - Rajesh Kumar Dutta
- Division of Cell Biology and Immunology, CSIR-Institute of Microbial Technology, Chandigarh 160 036, India
| | - Sekhar Majumdar
- Division of Cell Biology and Immunology, CSIR-Institute of Microbial Technology, Chandigarh 160 036, India.
| |
Collapse
|
37
|
Jiang N, Xue R, Bu F, Tong X, Qiang J, Liu R. Decreased RGS6 expression is associated with poor prognosis in pancreatic cancer patients. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2014; 7:4120-4127. [PMID: 25120791 PMCID: PMC4129026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/25/2014] [Indexed: 06/03/2023]
Abstract
Regulator of G-protein signaling 6 (RGS6), a member of a family of RGS proteins, has been reported to involve in multiple processes during tumor development. However, its role in pancreatic cancer has not been studied yet. In this study, we aimed to investigate the expression of RGS6 in pancreatic cancer and its role in predicting outcomes of patients with pancreatic cancer. We first measured the expression of RGS6 mRNA in 20 cases of tumor tissues and matched adjacent non-tumorous tissues by quantitative real-time PCR and examined RGS6 protein by immunohistochemistry in tissue microarrays containing 90 tumor and 90 paired adjacent non-tumor tissues. Decreased RGS6 mRNA detected in primary tumor, compared with their non-tumor counterparts. In addition, decreased RGS6 protein expression was associated with tumor differentiation (P = 0.027), pT classification (P = 0.034), smoking status (P = 0.041) and a poor survival (P = 0.007). Cox proportional hazards regression modeling analysis revealed that lymph node metastasis (P = 0.001; hazard ratio, 2.347, 95% CI, 1.387-3.972), tumor differentiation (P = 0.015; hazard ratio, 0.505, 95% CI, 0.291-0.876) and RGS6 expression (P = 0.048; hazard ratio, 0.567, 95% CI, 0.324-0.994) were three independent prognostic factors. Taken together, these date demonstrate that RGS6 decreases in tumor tissue and may serve as a novel biomarker for outcomes in pancreatic cancer patients and be a potential therapeutic target potential therapeutic target.
Collapse
Affiliation(s)
- Nan Jiang
- Department of Surgical Oncology, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Ruihua Xue
- Department of Surgical Oncology, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Fangfang Bu
- Department of Cancer Center, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Xin Tong
- Department of Cancer Center, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Jiankun Qiang
- Department of Cancer Center, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Rong Liu
- Department of Surgical Oncology, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| |
Collapse
|
38
|
Jeong W, Lim W, Ahn SE, Lim CH, Lee JY, Bae SM, Kim J, Bazer FW, Song G. Recrudescence mechanisms and gene expression profile of the reproductive tracts from chickens during the molting period. PLoS One 2013; 8:e76784. [PMID: 24098561 PMCID: PMC3788108 DOI: 10.1371/journal.pone.0076784] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/03/2013] [Indexed: 02/04/2023] Open
Abstract
The reproductive system of chickens undergoes dynamic morphological and functional tissue remodeling during the molting period. The present study identified global gene expression profiles following oviductal tissue regression and regeneration in laying hens in which molting was induced by feeding high levels of zinc in the diet. During the molting and recrudescence processes, progressive morphological and physiological changes included regression and re-growth of reproductive organs and fluctuations in concentrations of testosterone, progesterone, estradiol and corticosterone in blood. The cDNA microarray analysis of oviductal tissues revealed the biological significance of gene expression-based modulation in oviductal tissue during its remodeling. Based on the gene expression profiles, expression patterns of selected genes such as, TF, ANGPTL3, p20K, PTN, AvBD11 and SERPINB3 exhibited similar patterns in expression with gradual decreases during regression of the oviduct and sequential increases during resurrection of the functional oviduct. Also, miR-1689* inhibited expression of Sp1, while miR-17-3p, miR-22* and miR-1764 inhibited expression of STAT1. Similarly, chicken miR-1562 and miR-138 reduced the expression of ANGPTL3 and p20K, respectively. These results suggest that these differentially regulated genes are closely correlated with the molecular mechanism(s) for development and tissue remodeling of the avian female reproductive tract, and that miRNA-mediated regulation of key genes likely contributes to remodeling of the avian reproductive tract by controlling expression of those genes post-transcriptionally. The discovered global gene profiles provide new molecular candidates responsible for regulating morphological and functional recrudescence of the avian reproductive tract, and provide novel insights into understanding the remodeling process at the genomic and epigenomic levels.
Collapse
Affiliation(s)
- Wooyoung Jeong
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Whasun Lim
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Suzie E. Ahn
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Chul-Hong Lim
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Jin-Young Lee
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Seung-Min Bae
- Department of Animal Biotechnology, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Jinyoung Kim
- Department of Animal Resources Science, Dankook University, Cheonan, Republic of Korea
| | - Fuller W. Bazer
- Center for Animal Biotechnology and Genomics and Department of Animal Science, Texas A&M University, College Station, Texas, United States of America
| | - Gwonhwa Song
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| |
Collapse
|
39
|
Huang J, Stewart A, Maity B, Hagen J, Fagan RL, Yang J, Quelle DE, Brenner C, Fisher RA. RGS6 suppresses Ras-induced cellular transformation by facilitating Tip60-mediated Dnmt1 degradation and promoting apoptosis. Oncogene 2013; 33:3604-11. [PMID: 23995786 DOI: 10.1038/onc.2013.324] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 04/16/2013] [Accepted: 07/04/2013] [Indexed: 12/17/2022]
Abstract
The RAS protooncogene has a central role in regulation of cell proliferation, and point mutations leading to oncogenic activation of Ras occur in a large number of human cancers. Silencing of tumor-suppressor genes by DNA methyltransferase 1 (Dnmt1) is essential for oncogenic cellular transformation by Ras, and Dnmt1 is overexpressed in numerous human cancers. Here we provide new evidence that the pleiotropic regulator of G protein signaling (RGS) family member RGS6 suppresses Ras-induced cellular transformation by facilitating Tip60-mediated degradation of Dmnt1 and promoting apoptosis. Employing mouse embryonic fibroblasts from wild-type and RGS6(-/-) mice, we found that oncogenic Ras induced upregulation of RGS6, which in turn blocked Ras-induced cellular transformation. RGS6 functions to suppress cellular transformation in response to oncogenic Ras by downregulating Dnmt1 protein expression leading to inhibition of Dnmt1-mediated anti-apoptotic activity. Further experiments showed that RGS6 functions as a scaffolding protein for both Dnmt1 and Tip60 and is required for Tip60-mediated acetylation of Dnmt1 and subsequent Dnmt1 ubiquitylation and degradation. The RGS domain of RGS6, known only for its GTPase-activating protein activity toward Gα subunits, was sufficient to mediate Tip60 association with RGS6. This work demonstrates a novel signaling action for RGS6 in negative regulation of oncogene-induced transformation and provides new insights into our understanding of the mechanisms underlying Ras-induced oncogenic transformation and regulation of Dnmt1 expression. Importantly, these findings identify RGS6 as an essential cellular defender against oncogenic stress and a potential therapeutic target for developing new cancer treatments.
Collapse
Affiliation(s)
- J Huang
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - A Stewart
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - B Maity
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - J Hagen
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - R L Fagan
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - J Yang
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - D E Quelle
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - C Brenner
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - R A Fisher
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| |
Collapse
|
40
|
Choi H, Jung C, Sohn SK, Kim S, Kim HJ, Kim YK, Kim T, Zhang Z, Shin ES, Lee JE, Moon JH, Kim SH, Kim KH, Mun YC, Kim H, Park J, Kim J, Kim DDH. Genome-wide genotype-based risk model for survival in acute myeloid leukaemia patients with normal karyotype. Br J Haematol 2013; 163:62-71. [DOI: 10.1111/bjh.12492] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Hangseok Choi
- Department of Long-Term Care Claims Review; National Health Insurance Corporation; Seoul; Korea
| | - Chulwon Jung
- Division of Haematology/Oncology; Department of Medicine; Samsung Medical Centre; Sungkyunkwan University School of Medicine; Seoul; Korea
| | - Sang Kyun Sohn
- Department of Haematology/Oncology; Kyungpook National University Hospital; Kyungpook National University; Daegu; Korea
| | - Seonwoo Kim
- Biostatistical team; Samsung Medical Centre; Samsung Biomedical Research Institute; Seoul; Korea
| | - Hyeoung-Joon Kim
- Department of Haematology/Oncology; Chonnam National University Hwasun Hospital; Chonnam National University; Hwasun; Korea
| | - Yeo-Kyeoung Kim
- Department of Haematology/Oncology; Chonnam National University Hwasun Hospital; Chonnam National University; Hwasun; Korea
| | - TaeHyung Kim
- Department of Bioinformatics; Donnelley Center; University of Toronto; Toronto; ON; Canada
| | - Zhaolei Zhang
- Department of Bioinformatics; Donnelley Center; University of Toronto; Toronto; ON; Canada
| | | | | | - Joon Ho Moon
- Department of Haematology/Oncology; Kyungpook National University Hospital; Kyungpook National University; Daegu; Korea
| | - Sung Hyun Kim
- Department of Haematology/Oncology; DongA University Medical Centre; DongA University; Busan; Korea
| | - Kyoung Ha Kim
- Department of Haematology/Oncology; Soonchunhyang University Seoul Hospital; Seoul; Korea
| | - Yeung-Chul Mun
- Department of Haematology/Oncology; Ewha Womans University School of Medicine; Seoul; Korea
| | - Hawk Kim
- Division of Hematology and Hematological Malignancies; Ulsan University Hospital; University of Ulsan College of Medicine; Ulsan; Korea
| | - Jinny Park
- Department of Haematology/Oncology; Gachon University Gil Hospital; Incheon; Korea
| | - Jhingook Kim
- Samsung Medical Centre; Samsung Cancer Research Institute; Seoul; Korea
| | | |
Collapse
|
41
|
Maity B, Stewart A, O'Malley Y, Askeland RW, Sugg SL, Fisher RA. Regulator of G protein signaling 6 is a novel suppressor of breast tumor initiation and progression. Carcinogenesis 2013; 34:1747-55. [PMID: 23598467 DOI: 10.1093/carcin/bgt128] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Breast cancer is a large global health burden and the most frequently diagnosed malignancy in women worldwide. Here, we utilize RGS6(-/-) mice to interrogate the role of regulator of G protein signaling 6 (RGS6), localized to the ductal epithelium in mouse and human breast, as a novel tumor suppressor in vivo. RGS6(-/-) mice exhibit accelerated 7,12-dimethylbenza[α]anthracene (DMBA)-induced tumor initiation and progression, as well as decreased overall survival. Analysis of carcinogenic aberrations in the mammary glands of DMBA-treated mice revealed a failure of the DNA damage response concurrent with augmented oncogenesis in RGS6(-/-) animals. Furthermore, RGS6 suppressed cell growth induced by either human epidermal growth factor receptor 2 or estrogen receptor activation in both MCF-7 breast cancer cells and mammary epithelial cells (MECs). MECs isolated from RGS6(-/-) mice also showed a deficit in DMBA-induced ATM/p53 activation, reactive oxygen species generation and apoptosis confirming that RGS6 is required for effective activation of the DNA damage response in these cells, a critical countermeasure against carcinogen-mediated genotoxic stress. The ability of RGS6 to simultaneously enhance DNA-damage-induced apoptotic signaling and suppress oncogenic cell growth likely underlie the accelerated tumorigenesis and cellular transformation observed in DMBA-treated RGS6(-/-) mice and isolated MECs, respectively. Unsurprisingly, spontaneous tumor formation was also seen in old female RGS6(-/-) but not in wild-type mice. Our finding that RGS6 is downregulated in all human breast cancer subtypes independent of their molecular classification indicates that obtaining a means to restore the growth suppressive and pro-apoptotic actions of RGS6 in breast might be a viable means to treat a large spectrum of breast tumors.
Collapse
Affiliation(s)
- Biswanath Maity
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | | | | | | | | | | |
Collapse
|
42
|
Kim J, Sohn I, Son DS, Kim DH, Ahn T, Jung SH. Prediction of a time-to-event trait using genome wide SNP data. BMC Bioinformatics 2013; 14:58. [PMID: 23418752 PMCID: PMC3651372 DOI: 10.1186/1471-2105-14-58] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 02/12/2013] [Indexed: 02/07/2023] Open
Abstract
Background A popular objective of many high-throughput genome projects is to discover various genomic markers associated with traits and develop statistical models to predict traits of future patients based on marker values. Results In this paper, we present a prediction method for time-to-event traits using genome-wide single-nucleotide polymorphisms (SNPs). We also propose a MaxTest associating between a time-to-event trait and a SNP accounting for its possible genetic models. The proposed MaxTest can help screen out nonprognostic SNPs and identify genetic models of prognostic SNPs. The performance of the proposed method is evaluated through simulations. Conclusions In conjunction with the MaxTest, the proposed method provides more parsimonious prediction models but includes more prognostic SNPs than some naive prediction methods. The proposed method is demonstrated with real GWAS data.
Collapse
Affiliation(s)
- Jinseog Kim
- Department of Statistics and Information Science, Dongguk University, Gyeongju 780-714, Korea
| | | | | | | | | | | |
Collapse
|
43
|
Yang J, Maity B, Huang J, Gao Z, Stewart A, Weiss RM, Anderson ME, Fisher RA. G-protein inactivator RGS6 mediates myocardial cell apoptosis and cardiomyopathy caused by doxorubicin. Cancer Res 2013; 73:1662-7. [PMID: 23338613 DOI: 10.1158/0008-5472.can-12-3453] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Clinical use of the widely used chemotherapeutic agent doxorubicin is limited by life-threatening cardiotoxicity. The mechanisms underlying doxorubicin-induced cardiomyopathy and heart failure remain unclear but are thought to involve p53-mediated myocardial cell apoptosis. The tripartite G-protein inactivating protein RGS6 has been implicated in reactive oxygen species (ROS) generation, ATM/p53 activation, and apoptosis in doxorubicin-treated cells. Thus, we hypothesized that RGS6, the expression of which is enriched in cardiac tissue, might also be responsible for the pathologic effects of doxorubicin treatment in heart. In this study, we show that RGS6 expression is induced strongly by doxorubicin in the ventricles of mice and isolated ventricular myocytes via a posttranscriptional mechanism. While doxorubicin-treated wild-type (WT) mice manifested severe left ventricular dysfunction, loss of heart and body mass, along with decreased survival 5 days after doxorubicin administration, mice lacking RGS6 were completely protected against these pathogenic responses. Activation of ATM/p53 apoptosis signaling by doxorubicin in ventricles of WT mice was also absent in their RGS6(-/-) counterparts. Doxorubicin-induced ROS generation was dramatically impaired in both the ventricles and ventricular myocytes isolated from RGS6(-/-) mice, and the apoptotic response to doxorubicin in ventricular myocytes required RGS6-dependent ROS production. These results identify RGS6 as an essential mediator of the pathogenic responses to doxorubicin in heart, and they argue that RGS6 inhibition offers a rational means to circumvent doxorubicin cardiotoxicity in human patients with cancer.
Collapse
Affiliation(s)
- Jianqi Yang
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242, USA
| | | | | | | | | | | | | | | |
Collapse
|
44
|
Castellarin M, Milne K, Zeng T, Tse K, Mayo M, Zhao Y, Webb JR, Watson PH, Nelson BH, Holt RA. Clonal evolution of high-grade serous ovarian carcinoma from primary to recurrent disease. J Pathol 2012; 229:515-24. [PMID: 22996961 DOI: 10.1002/path.4105] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/17/2012] [Accepted: 09/11/2012] [Indexed: 01/04/2023]
Abstract
High-grade serous carcinoma (HGSC) is the most common and fatal form of ovarian cancer. While most tumours are highly sensitive to cytoreductive surgery and platinum- and taxane-based chemotherapy, the majority of patients experience recurrence of treatment-resistant tumours. The clonal origin and mutational adaptations associated with recurrent disease are poorly understood. We performed whole exome sequencing on tumour cells harvested from ascites at three time points (primary, first recurrence, and second recurrence) for three HGSC patients receiving standard treatment. Somatic point mutations and small insertions and deletions were identified by comparison to constitutional DNA. The clonal structure and evolution of tumours were inferred from patterns of mutant allele frequencies. TP53 mutations were predominant in all patients at all time points, consistent with the known founder role of this gene. Tumours from all three patients also harboured mutations associated with cell cycle checkpoint function and Golgi vesicle trafficking. There was convergence of germline and somatic variants within the DNA repair, ECM, cell cycle control, and Golgi vesicle pathways. The vast majority of somatic variants found in recurrent tumours were present in primary tumours. Our findings highlight both known and novel pathways that are commonly mutated in HGSC. Moreover, they provide the first evidence at single nucleotide resolution that recurrent HGSC arises from multiple clones present in the primary tumour with negligible accumulation of new mutations during standard treatment.
Collapse
Affiliation(s)
- Mauro Castellarin
- BC Cancer Agency, Michael Smith Genome Sciences Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1 L3, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Stewart A, Huang J, Fisher RA. RGS Proteins in Heart: Brakes on the Vagus. Front Physiol 2012; 3:95. [PMID: 22685433 PMCID: PMC3368389 DOI: 10.3389/fphys.2012.00095] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 03/27/2012] [Indexed: 12/14/2022] Open
Abstract
It has been nearly a century since Otto Loewi discovered that acetylcholine (ACh) release from the vagus produces bradycardia and reduced cardiac contractility. It is now known that parasympathetic control of the heart is mediated by ACh stimulation of G(i/o)-coupled muscarinic M2 receptors, which directly activate G protein-coupled inwardly rectifying potassium (GIRK) channels via Gβγ resulting in membrane hyperpolarization and inhibition of action potential (AP) firing. However, expression of M2R-GIRK signaling components in heterologous systems failed to recapitulate native channel gating kinetics. The missing link was identified with the discovery of regulator of G protein signaling (RGS) proteins, which act as GTPase-activating proteins to accelerate the intrinsic GTPase activity of Gα resulting in termination of Gα- and Gβγ-mediated signaling to downstream effectors. Studies in mice expressing an RGS-insensitive Gα(i2) mutant (G184S) implicated endogenous RGS proteins as key regulators of parasympathetic signaling in heart. Recently, two RGS proteins have been identified as critical regulators of M2R signaling in heart. RGS6 exhibits a uniquely robust expression in heart, especially in sinoatrial (SAN) and atrioventricular nodal regions. Mice lacking RGS6 exhibit increased bradycardia and inhibition of SAN AP firing in response to CCh as well as a loss of rapid activation and deactivation kinetics and current desensitization for ACh-induced GIRK current (I(KACh)). Similar findings were observed in mice lacking RGS4. Thus, dysregulation in RGS protein expression or function may contribute to pathologies involving aberrant electrical activity in cardiac pacemaker cells. Moreover, RGS6 expression was found to be up-regulated in heart under certain pathological conditions, including doxorubicin treatment, which is known to cause life-threatening cardiotoxicity and atrial fibrillation in cancer patients. On the other hand, increased vagal tone may be cardioprotective in heart failure where acetylcholinesterase inhibitors and vagal stimulation have been proposed as potential therapeutics. Together, these studies identify RGS proteins, especially RGS6, as new therapeutic targets for diseases such as sick sinus syndrome or other maladies involving abnormal autonomic control of the heart.
Collapse
Affiliation(s)
- Adele Stewart
- Department of Pharmacology, Carver College of Medicine, University of Iowa Iowa City, IA, USA
| | | | | |
Collapse
|
46
|
Maity B, Stewart A, Yang J, Loo L, Sheff D, Shepherd AJ, Mohapatra DP, Fisher RA. Regulator of G protein signaling 6 (RGS6) protein ensures coordination of motor movement by modulating GABAB receptor signaling. J Biol Chem 2011; 287:4972-81. [PMID: 22179605 DOI: 10.1074/jbc.m111.297218] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
γ-Aminobutyric acid (GABA) release from inhibitory interneurons located within the cerebellar cortex limits the extent of neuronal excitation in part through activation of metabotropic GABA(B) receptors. Stimulation of these receptors triggers a number of downstream signaling events, including activation of GIRK channels by the Gβγ dimer resulting in membrane hyperpolarization and inhibition of neurotransmitter release from presynaptic sites. Here, we identify RGS6, a member of the R7 subfamily of RGS proteins, as a key regulator of GABA(B)R signaling in cerebellum. RGS6 is enriched in the granule cell layer of the cerebellum along with neuronal GIRK channel subunits 1 and 2 where RGS6 forms a complex with known binding partners Gβ(5) and R7BP. Mice lacking RGS6 exhibit abnormal gait and ataxia characterized by impaired rotarod performance improved by treatment with a GABA(B)R antagonist. RGS6(-/-) mice administered baclofen also showed exaggerated motor coordination deficits compared with their wild-type counterparts. Isolated cerebellar neurons natively expressed RGS6, GABA(B)R, and GIRK channel subunits, and cerebellar granule neurons from RGS6(-/-) mice showed a significant delay in the deactivation kinetics of baclofen-induced GIRK channel currents. These results establish RGS6 as a key component of GABA(B)R signaling and represent the first demonstration of an essential role for modulatory actions of RGS proteins in adult cerebellum. Dysregulation of RGS6 expression in human patients could potentially contribute to loss of motor coordination and, thus, pharmacological manipulation of RGS6 levels might represent a viable means to treat patients with ataxias of cerebellar origin.
Collapse
Affiliation(s)
- Biswanath Maity
- Department of Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Huang J, Yang J, Maity B, Mayuzumi D, Fisher RA. Regulator of G protein signaling 6 mediates doxorubicin-induced ATM and p53 activation by a reactive oxygen species-dependent mechanism. Cancer Res 2011; 71:6310-9. [PMID: 21859827 DOI: 10.1158/0008-5472.can-10-3397] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Doxorubicin (DXR), among the most widely used cancer chemotherapy agents, promotes cancer cell death via activation of ataxia telangiectasia mutated (ATM) and the resultant upregulation of tumor suppressor p53. The exact mechanism by which DXR activates ATM is not fully understood. Here, we discovered a novel role for regulator of G protein signaling 6 (RGS6) in mediating activation of ATM and p53 by DXR. RGS6 was robustly induced by DXR, and genetic loss of RGS6 dramatically impaired DXR-induced activation of ATM and p53, as well as its in vivo apoptotic actions in heart. The ability of RGS6 to promote p53 activation in response to DXR was independent of RGS6 interaction with G proteins but required ATM. RGS6 mediated activation of ATM and p53 by DXR via a reactive oxygen species (ROS)-dependent and DNA damage-independent mechanism. This mechanism represents the primary means by which DXR promotes activation of the ATM-p53 apoptosis pathway that underlies its cytotoxic activity. Our findings contradict the canonical theories that DXR activates ATM primarily by promoting DNA damage either directly or indirectly (via ROS) and that RGS6 function is mediated by its interactions with G proteins. These findings reveal a new mechanism for the chemotherapeutic actions of DXR and identify RGS6 as a novel target for cancer chemotherapy.
Collapse
Affiliation(s)
- Jie Huang
- Department of Pharmacology, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242, USA
| | | | | | | | | |
Collapse
|