1
|
Baraghithy S, Soae Y, Assaf D, Hinden L, Udi S, Drori A, Gabet Y, Tam J. Renal Proximal Tubule Cell Cannabinoid-1 Receptor Regulates Bone Remodeling and Mass via a Kidney-to-Bone Axis. Cells 2021; 10:414. [PMID: 33671138 PMCID: PMC7922053 DOI: 10.3390/cells10020414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/07/2021] [Accepted: 02/13/2021] [Indexed: 12/20/2022] Open
Abstract
The renal proximal tubule cells (RPTCs), well-known for maintaining glucose and mineral homeostasis, play a critical role in the regulation of kidney function and bone remodeling. Deterioration in RPTC function may therefore lead to the development of diabetic kidney disease (DKD) and osteoporosis. Previously, we have shown that the cannabinoid-1 receptor (CB1R) modulates both kidney function as well as bone remodeling and mass via its direct role in RPTCs and bone cells, respectively. Here we employed genetic and pharmacological approaches that target CB1R, and found that its specific nullification in RPTCs preserves bone mass and remodeling both under normo- and hyper-glycemic conditions, and that its chronic blockade prevents the development of diabetes-induced bone loss. These protective effects of negatively targeting CB1R specifically in RPTCs were associated with its ability to modulate erythropoietin (EPO) synthesis, a hormone known to affect bone mass and remodeling. Our findings highlight a novel molecular mechanism by which CB1R in RPTCs remotely regulates skeletal homeostasis via a kidney-to-bone axis that involves EPO.
Collapse
Affiliation(s)
- Saja Baraghithy
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Yael Soae
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Dekel Assaf
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Liad Hinden
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Shiran Udi
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Adi Drori
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Yankel Gabet
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel;
| | - Joseph Tam
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| |
Collapse
|
2
|
Drori A, Gammal A, Azar S, Hinden L, Hadar R, Wesley D, Nemirovski A, Szanda G, Salton M, Tirosh B, Tam J. CB 1R regulates soluble leptin receptor levels via CHOP, contributing to hepatic leptin resistance. eLife 2020; 9:60771. [PMID: 33210603 PMCID: PMC7728447 DOI: 10.7554/elife.60771] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/17/2020] [Indexed: 12/22/2022] Open
Abstract
The soluble isoform of leptin receptor (sOb-R), secreted by the liver, regulates leptin bioavailability and bioactivity. Its reduced levels in diet-induced obesity (DIO) contribute to hyperleptinemia and leptin resistance, effects that are regulated by the endocannabinoid (eCB)/CB1R system. Here we show that pharmacological activation/blockade and genetic overexpression/deletion of hepatic CB1R modulates sOb-R levels and hepatic leptin resistance. Interestingly, peripheral CB1R blockade failed to reverse DIO-induced reduction of sOb-R levels, increased fat mass and dyslipidemia, and hepatic steatosis in mice lacking C/EBP homologous protein (CHOP), whereas direct activation of CB1R in wild-type hepatocytes reduced sOb-R levels in a CHOP-dependent manner. Moreover, CHOP stimulation increased sOb-R expression and release via a direct regulation of its promoter, while CHOP deletion reduced leptin sensitivity. Our findings highlight a novel molecular aspect by which the hepatic eCB/CB1R system is involved in the development of hepatic leptin resistance and in the regulation of sOb-R levels via CHOP. When the human body has stored enough energy from food, it releases a hormone called leptin that travels to the brain and stops feelings of hunger. This hormone moves through the bloodstream and can affect other organs, such as the liver, which also help control our body’s energy levels. Most people with obesity have very high levels of leptin in their blood, but are resistant to its effects and will therefore continue to feel hungry despite having stored enough energy. One of the proteins that controls the levels of leptin is a receptor called sOb-R, which is released by the liver and binds to leptin as it travels in the blood. Individuals with high levels of this receptor often have less free leptin in their bloodstream and a lower body weight. Another protein that helps the body to regulate its energy levels is the cannabinoid-1 receptor, or CB1R for short. In people with obesity, this receptor is overactive and has been shown to contribute to leptin resistance, which is when the brain becomes less receptive to leptin. Previous work in mice showed that blocking CB1R reduced the levels of leptin and allowed mice to react to this hormone normally again, but it remained unclear whether CB1R affects how other organs, such as the liver, respond to leptin. To answer this question, Drori et al. blocked the CB1R receptor in the liver of mice eating a high-fat diet, either by using a drug or by deleting the gene that codes for this protein. This caused mice to have higher levels of sOb-R circulating in their bloodstream. Further experiments showed that this change in sOb-R was caused by the levels of a protein called CHOP increasing in the liver when CB1R was blocked. Drori et al. found that inhibiting CB1R caused these obese mice to lose weight and have healthier, less fatty livers as a result of their livers no longer being resistant to the effects of leptin. Scientists, doctors and pharmaceutical companies are trying to develop new strategies to combat obesity. The results from these experiments suggest that blocking CB1R in the liver could allow this organ to react to leptin appropriately again. Drugs blocking CB1R, including the one used in this study, will be tested in clinical trials and could provide a new approach for treating obesity.
Collapse
Affiliation(s)
- Adi Drori
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Asaad Gammal
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shahar Azar
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Liad Hinden
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rivka Hadar
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Daniel Wesley
- Laboratory of Physiological Studies, National Institute on Alcohol Abuse & Alcoholism, Bethesda, United States
| | - Alina Nemirovski
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Gergő Szanda
- MTA-SE Laboratory of Molecular Physiology, Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Maayan Salton
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Boaz Tirosh
- The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Joseph Tam
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|
3
|
Azar S, Udi S, Drori A, Hadar R, Nemirovski A, Vemuri KV, Miller M, Sherill-Rofe D, Arad Y, Gur-Wahnon D, Li X, Makriyannis A, Ben-Zvi D, Tabach Y, Ben-Dov IZ, Tam J. Reversal of diet-induced hepatic steatosis by peripheral CB1 receptor blockade in mice is p53/miRNA-22/SIRT1/PPARα dependent. Mol Metab 2020; 42:101087. [PMID: 32987186 PMCID: PMC7563015 DOI: 10.1016/j.molmet.2020.101087] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/03/2020] [Accepted: 09/17/2020] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE The endocannabinoid (eCB) system is increasingly recognized as being crucially important in obesity-related hepatic steatosis. By activating the hepatic cannabinoid-1 receptor (CB1R), eCBs modulate lipogenesis and fatty acid oxidation. However, the underlying molecular mechanisms are largely unknown. METHODS We combined unbiased bioinformatics techniques, mouse genetic manipulations, multiple pharmacological, molecular, and cellular biology approaches, and genomic sequencing to systematically decipher the role of the hepatic CB1R in modulating fat utilization in the liver and explored the downstream molecular mechanisms. RESULTS Using an unbiased normalized phylogenetic profiling analysis, we found that the CB1R evolutionarily coevolves with peroxisome proliferator-activated receptor-alpha (PPARα), a key regulator of hepatic lipid metabolism. In diet-induced obese (DIO) mice, peripheral CB1R blockade (using AM6545) induced the reversal of hepatic steatosis and improved liver injury in WT, but not in PPARα-/- mice. The antisteatotic effect mediated by AM6545 in WT DIO mice was accompanied by increased hepatic expression and activity of PPARα as well as elevated hepatic levels of the PPARα-activating eCB-like molecules oleoylethanolamide and palmitoylethanolamide. Moreover, AM6545 was unable to rescue hepatic steatosis in DIO mice lacking liver sirtuin 1 (SIRT1), an upstream regulator of PPARα. Both of these signaling molecules were modulated by the CB1R as measured in hepatocytes exposed to lipotoxic conditions or treated with CB1R agonists in the absence/presence of AM6545. Furthermore, using microRNA transcriptomic profiling, we found that the CB1R regulated the hepatic expression, acetylation, and transcriptional activity of p53, resulting in the enhanced expression of miR-22, which was found to specifically target SIRT1 and PPARα. CONCLUSIONS We provide strong evidence for a functional role of the p53/miR-22/SIRT1/PPARα signaling pathway in potentially mediating the antisteatotic effect of peripherally restricted CB1R blockade.
Collapse
Affiliation(s)
- Shahar Azar
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shiran Udi
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adi Drori
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rivka Hadar
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alina Nemirovski
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Kiran V Vemuri
- Center for Drug Discovery, Northeastern University, Boston, MA, USA
| | - Maya Miller
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dana Sherill-Rofe
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yhara Arad
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Devorah Gur-Wahnon
- Laboratory of Medical Transcriptomics, Department of Nephrology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Xiaoling Li
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | | | - Danny Ben-Zvi
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Iddo Z Ben-Dov
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Joseph Tam
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
| |
Collapse
|
4
|
Korotun M, Weizman L, Drori A, Zaccaria J, Goldstein T, Litman I, Hahn S, Greenberg H. 0584 Detecting Sleep Disordered Breathing Using Sub-Terahertz Radio-Frequency Micro-Radar. Sleep 2020. [DOI: 10.1093/sleep/zsaa056.581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Introduction
New sensor technologies are entering sleep testing at a rapid pace; Neteera™ developed a novel sensor and algorithm for sleep apnea detection utilizing a contact-free, radar-based sensor system. The system utilizes a high-frequency, low-power, directional micro-radar which operates at ~120GHz and a sampling rate of 2500Hz as well as algorithms which are able to detect both pulse and respiratory activity of subjects during sleep.
Methods
Adult subjects undergoing diagnostic PSG for clinical purposes were simultaneously assessed with the novel micro-radar system with sensors under the mattress. Disordered breathing events (DBEs) were scored from the PSG using AASM scoring guidelines and were compared with those detected by the micro-radar sensor. Test data were grouped into three sets: 1. Single under mattress sensor; 2. Two under mattress sensors on each side of the bed (to improve signal capture); 3. After software optimization. The micro-radar sensor detected DBEs but software to describe the type of DBEs (obstructive apnea/central apnea/hypopnea) is still under development. Detection rate of DBEs was compared between the two methodologies and the development sets.
Results
n=22 (12 F, 10 M), Age=50.8±12.4 years, BMI=35.32±7.37 kg/m2. Diagnostic PSG AHI: 19.7±29.4/hr, T90=15.8±25.7%. Percent DBEs missed by the micro-radar sensor: 1st set=14.6±10.6%; 2nd set=9.4±8.3%; 3rd set=1.2±2.6%. Number of DBEs assessed for each set was 646, 1144, 125 events, respectively. With each successive set, the detection rate improved.
Conclusion
A novel micro-radar, non-contact sensor technology can be used to detect DBEs during sleep. Detection rate improved with utilization of two sensors per bed and software optimization. Future software development is expected to improve detection rate and facilitate breathing event classification into obstructive apneas/central apneas/hypopneas.
Support
None.
Collapse
Affiliation(s)
| | - L Weizman
- Neteera Technologies Ltd., Jerusalem, ISRAEL
| | - A Drori
- Neteera Technologies Ltd., Jerusalem, ISRAEL
| | - J Zaccaria
- Neteera Technologies Ltd., Jerusalem, ISRAEL
| | | | - I Litman
- Neteera Technologies Ltd., Jerusalem, ISRAEL
| | - S Hahn
- Northwell Health, New Hyde Park, NY
| | | |
Collapse
|
5
|
Udi S, Hinden L, Ahmad M, Drori A, Iyer MR, Cinar R, Herman-Edelstein M, Tam J. Dual inhibition of cannabinoid CB 1 receptor and inducible NOS attenuates obesity-induced chronic kidney disease. Br J Pharmacol 2019; 177:110-127. [PMID: 31454063 PMCID: PMC6976880 DOI: 10.1111/bph.14849] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 08/21/2019] [Accepted: 08/22/2019] [Indexed: 12/14/2022] Open
Abstract
Background and Purpose Obesity, an important risk factor for developing chronic kidney disease (CKD), affects the kidneys by two main molecular signalling pathways: the endocannabinoid/CB1 receptor system, whose activation in obesity promotes renal inflammation, fibrosis, and injury, and the inducible NOS (iNOS), which generates ROS resulting in oxidative stress. Hence, a compound that inhibits both peripheral CB1 receptors and iNOS may serve as an effective therapeutic agent against obesity‐induced CKD. Experimental Approach Here, we describe the effect of a novel peripherally restricted, orally bioavailable dual CB1 receptor/iNOS antagonist, MRI‐1867 (3 mg·kg−1), in ameliorating obesity‐induced CKD, and compared its metabolic and renal efficacies to a stand‐alone peripheral CB1 receptor antagonist (JD5037; 3 mg·kg−1), iNOS antagonist (1400W; 10 mg·kg−1), and pair feeding. Mice with high‐fat diet‐induced obesity were treated orally with these compounds or vehicle (Veh) for 28 days. Standard diet‐fed mice treated with Veh served as controls. Key Results Enhanced expression of CB1 receptors and iNOS in renal tubules was found in human kidney patients with obesity and other CKDs. The hybrid inhibitor ameliorated obesity‐induced kidney morphological and functional changes via decreasing kidney inflammation, fibrosis, oxidative stress, and renal injury. Some of these features were independent of the improved metabolic profile mediated via inhibition of CB1 receptors. An additional interesting finding is that these beneficial effects on the kidney were partially associated with modulating renal adiponectin signalling. Conclusions and Implications Collectively, our results highlight the therapeutic relevance of blocking CB1 receptors and iNOS in ameliorating obesity‐induced CKD.
Collapse
Affiliation(s)
- Shiran Udi
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Liad Hinden
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Majdoleen Ahmad
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adi Drori
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Malliga R Iyer
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Resat Cinar
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Michal Herman-Edelstein
- Department of Nephrology & Hypertension, Rabin Medical Center, Petah Tikva, Israel.,Sackler Medical School, Tel Aviv University, Tel Aviv, Israel
| | - Joseph Tam
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|
6
|
Baraghithy S, Smoum R, Drori A, Hadar R, Gammal A, Hirsch S, Attar-Namdar M, Nemirovski A, Gabet Y, Langer Y, Pollak Y, Schaaf CP, Rech ME, Gross-Tsur V, Bab I, Mechoulam R, Tam J. Magel2 Modulates Bone Remodeling and Mass in Prader-Willi Syndrome by Affecting Oleoyl Serine Levels and Activity. J Bone Miner Res 2019; 34:93-105. [PMID: 30347474 DOI: 10.1002/jbmr.3591] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/30/2018] [Accepted: 09/08/2018] [Indexed: 12/17/2022]
Abstract
Among a multitude of hormonal and metabolic complications, individuals with Prader-Willi syndrome (PWS) exhibit significant bone abnormalities, including decreased BMD, osteoporosis, and subsequent increased fracture risk. Here we show in mice that loss of Magel2, a maternally imprinted gene in the PWS critical region, results in reduced bone mass, density, and strength, corresponding to that observed in humans with PWS, as well as in individuals suffering from Schaaf-Yang syndrome (SYS), a genetic disorder caused by a disruption of the MAGEL2 gene. The low bone mass phenotype in Magel2-/- mice was attributed to reduced bone formation rate, increased osteoclastogenesis and osteoclast activity, and enhanced trans-differentiation of osteoblasts to adipocytes. The absence of Magel2 in humans and mice resulted in reduction in the fatty acid amide bone homeostasis regulator, N-oleoyl serine (OS), whose levels were positively linked with BMD in humans and mice as well as osteoblast activity. Attenuating the skeletal abnormalities in Magel2-/- mice was achieved with chronic administration of a novel synthetic derivative of OS. Taken together, Magel2 plays a key role in modulating bone remodeling and mass in PWS by affecting OS levels and activity. The use of potent synthetic analogs of OS should be further tested clinically as bone therapeutics for treating bone loss. © 2018 American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Saja Baraghithy
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Reem Smoum
- Medicinal Chemistry Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adi Drori
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rivka Hadar
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Asaad Gammal
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shira Hirsch
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Malka Attar-Namdar
- Bone Laboratory, Institute for Dental Research, Faculty of Dentistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alina Nemirovski
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yankel Gabet
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Yshaia Langer
- Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Yehuda Pollak
- Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Christian Patrick Schaaf
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Megan Elizabeth Rech
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Varda Gross-Tsur
- Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Itai Bab
- Bone Laboratory, Institute for Dental Research, Faculty of Dentistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Raphael Mechoulam
- Medicinal Chemistry Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Joseph Tam
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|
7
|
Drori A, Permyakova A, Hadar R, Udi S, Nemirovski A, Tam J. Cannabinoid-1 receptor regulates mitochondrial dynamics and function in renal proximal tubular cells. Diabetes Obes Metab 2019; 21:146-159. [PMID: 30091204 PMCID: PMC6586028 DOI: 10.1111/dom.13497] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 12/22/2022]
Abstract
AIMS To evaluate the specific role of the endocannabinoid/cannabinoid type-1 (CB1 R) system in modulating mitochondrial dynamics in the metabolically active renal proximal tubular cells (RPTCs). MATERIALS AND METHODS We utilized mitochondrially-targeted GFP in live cells (wild-type and null for the CB1 R) and electron microscopy in kidney sections of RPTC-CB1 R-/- mice and their littermate controls. In both in vitro and in vivo conditions, we assessed the ability of CB1 R agonism or fatty acid flux to modulate mitochondrial architecture and function. RESULTS Direct stimulation of CB1 R resulted in mitochondrial fragmentation in RPTCs. This process was mediated, at least in part, by modulating the phosphorylation levels of the canonical fission protein dynamin-related protein 1 on both S637 and S616 residues. CB1 R-induced mitochondrial fission was associated with mitochondrial dysfunction, as documented by reduced oxygen consumption and ATP production, increased reactive oxygen species and cellular lactate levels, as well as a decline in mitochondrial biogenesis. Likewise, we documented that exposure of RPTCs to a fatty acid flux induced CB1 R-dependent mitochondrial fission, lipotoxicity and cellular dysfunction. CONCLUSIONS CB1 R plays a key role in inducing mitochondrial fragmentation in RPTCs, leading to a decline in the organelle's function and contributing to the renal tubular injury associated with lipotoxicity and other metabolic diseases.
Collapse
Affiliation(s)
- Adi Drori
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of MedicineThe Hebrew University of JerusalemJerusalemIsrael
| | - Anna Permyakova
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of MedicineThe Hebrew University of JerusalemJerusalemIsrael
| | - Rivka Hadar
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of MedicineThe Hebrew University of JerusalemJerusalemIsrael
| | - Shiran Udi
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of MedicineThe Hebrew University of JerusalemJerusalemIsrael
| | - Alina Nemirovski
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of MedicineThe Hebrew University of JerusalemJerusalemIsrael
| | - Joseph Tam
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of MedicineThe Hebrew University of JerusalemJerusalemIsrael
| |
Collapse
|
8
|
Tam J, Hinden L, Drori A, Udi S, Azar S, Baraghithy S. The therapeutic potential of targeting the peripheral endocannabinoid/CB 1 receptor system. Eur J Intern Med 2018; 49:23-29. [PMID: 29336868 DOI: 10.1016/j.ejim.2018.01.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/03/2018] [Accepted: 01/04/2018] [Indexed: 02/07/2023]
Abstract
Endocannabinoids (eCBs) are internal lipid mediators recognized by the cannabinoid-1 and -2 receptors (CB1R and CB2R, respectively), which also mediate the different physiological effects of marijuana. The endocannabinoid system, consisting of eCBs, their receptors, and the enzymes involved in their biosynthesis and degradation, is present in a vast number of peripheral organs. In this review we describe the role of the eCB/CB1R system in modulating the metabolism in several peripheral organs. We assess how eCBs, via activating the CB1R, contribute to obesity and regulate food intake. In addition, we describe their roles in modulating liver and kidney functions, as well as bone remodeling and mass. Special importance is given to emphasizing the efficacy of the recently developed peripherally restricted CB1R antagonists, which were pre-clinically tested in the management of energy homeostasis, and in ameliorating both obesity- and diabetes-induced metabolic complications.
Collapse
Affiliation(s)
- Joseph Tam
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
| | - Liad Hinden
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Adi Drori
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Shiran Udi
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Shahar Azar
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Saja Baraghithy
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| |
Collapse
|
9
|
Drori A, Rotnemer-Golinkin D, Avni S, Drori A, Danay O, Levanon D, Tam J, Zolotarev L, Ilan Y. Attenuating the rate of total body fat accumulation and alleviating liver damage by oral administration of vitamin D-enriched edible mushrooms in a diet-induced obesity murine model is mediated by an anti-inflammatory paradigm shift. BMC Gastroenterol 2017; 17:130. [PMID: 29179679 PMCID: PMC5704499 DOI: 10.1186/s12876-017-0688-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 11/17/2017] [Indexed: 02/08/2023] Open
Abstract
Background Hypovitaminosis D is associated with many features of the metabolic syndrome, including non-alcoholic fatty liver disease. Vitamin D-enriched mushrooms extracts exert a synergistic anti-inflammatory effect. The aim of the present study is to determine the immunomodulatory effect of oral administration of vitamin D-enriched mushrooms extracts on high-fat diet (HFD) animal model of non-alcoholic steatohepatitis (NASH). Methods C57BL/6 mice on HFD were orally administered with vitamin D supplement, Lentinula edodes (LE) mushrooms extract, or vitamin D-enriched mushrooms extract for 25 weeks. Mice were studied for the effect of the treatment on the immune system, liver functions and histology, insulin resistance and lipid profile. Results Treatment with vitamin D-enriched LE extracts was associated with significant attenuation of the rate of total body fat accumulation, along with a decrease in hepatic fat content as measured by an EchoMRI. Significant alleviation of liver damage manifested by a marked decrease in ALT, and AST serum levels (from 900 and 1021 U/L in the control group to 313 and 340; 294 and 292; and 366 and 321 U/L for ALT and AST, in Vit D, LE and LE + Vit D treated groups, respectively). A corresponding effect on hepatocyte ballooning were also noted. A significant decrease in serum triglycerides (from 103 to 75, 69 and 72 mg/dL), total cholesterol (from 267 to 160, 157 and 184 mg/dL), and LDL cholesterol (from 193 mg/dL to 133, 115 and 124 mg/dL) along with an increase in the HDL/LDL ratio, and improved glucose levels were documented. These beneficial effects were associated with a systemic immunomodulatory effect associated with an increased CD4/CD8 lymphocyte ratio (from 1.38 in the control group to 1.69, 1.71 and 1.63), and a pro- to an anti-inflammatory cytokine shift. Conclusions Oral administration of vitamin-D enriched mushrooms extracts exerts an immune modulatory hepato-protective effect in NASH model.
Collapse
Affiliation(s)
- A Drori
- Gastroenterology and Liver Units, Department of Medicine, Hadassah-Hebrew University Medical Center, P.O.B 12000, -91120, Jerusalem, IL, Israel
| | - D Rotnemer-Golinkin
- Gastroenterology and Liver Units, Department of Medicine, Hadassah-Hebrew University Medical Center, P.O.B 12000, -91120, Jerusalem, IL, Israel
| | - S Avni
- Migal, Galilee Research Institute, Kiryat Shmona, Israel
| | - A Drori
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - O Danay
- Migal, Galilee Research Institute, Kiryat Shmona, Israel
| | - D Levanon
- Migal, Galilee Research Institute, Kiryat Shmona, Israel
| | - J Tam
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - L Zolotarev
- Gastroenterology and Liver Units, Department of Medicine, Hadassah-Hebrew University Medical Center, P.O.B 12000, -91120, Jerusalem, IL, Israel
| | - Y Ilan
- Gastroenterology and Liver Units, Department of Medicine, Hadassah-Hebrew University Medical Center, P.O.B 12000, -91120, Jerusalem, IL, Israel.
| |
Collapse
|
10
|
Hinden L, Udi S, Drori A, Gammal A, Nemirovski A, Hadar R, Baraghithy S, Permyakova A, Geron M, Cohen M, Tsytkin-Kirschenzweig S, Riahi Y, Leibowitz G, Nahmias Y, Priel A, Tam J. Modulation of Renal GLUT2 by the Cannabinoid-1 Receptor: Implications for the Treatment of Diabetic Nephropathy. J Am Soc Nephrol 2017; 29:434-448. [PMID: 29030466 DOI: 10.1681/asn.2017040371] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/10/2017] [Indexed: 12/15/2022] Open
Abstract
Altered glucose reabsorption via the facilitative glucose transporter 2 (GLUT2) during diabetes may lead to renal proximal tubule cell (RPTC) injury, inflammation, and interstitial fibrosis. These pathologies are also triggered by activating the cannabinoid-1 receptor (CB1R), which contributes to the development of diabetic nephropathy (DN). However, the link between CB1R and GLUT2 remains to be determined. Here, we show that chronic peripheral CB1R blockade or genetically inactivating CB1Rs in the RPTCs ameliorated diabetes-induced renal structural and functional changes, kidney inflammation, and tubulointerstitial fibrosis in mice. Inhibition of CB1R also downregulated GLUT2 expression, affected the dynamic translocation of GLUT2 to the brush border membrane of RPTCs, and reduced glucose reabsorption. Thus, targeting peripheral CB1R or inhibiting GLUT2 dynamics in RPTCs has the potential to treat and ameliorate DN. These findings may support the rationale for the clinical testing of peripherally restricted CB1R antagonists or the development of novel renal-specific GLUT2 inhibitors against DN.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Matan Geron
- Cellular and Molecular Pain Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, and
| | - Merav Cohen
- The Alexander Grass Center for Bioengineering, Benin School of Computer and Science Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Cell and Developmental Biology, Silberman Institute of Life Sciences, Jerusalem, Israel; and
| | - Sabina Tsytkin-Kirschenzweig
- The Alexander Grass Center for Bioengineering, Benin School of Computer and Science Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Cell and Developmental Biology, Silberman Institute of Life Sciences, Jerusalem, Israel; and
| | - Yael Riahi
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Gil Leibowitz
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Yaakov Nahmias
- The Alexander Grass Center for Bioengineering, Benin School of Computer and Science Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Cell and Developmental Biology, Silberman Institute of Life Sciences, Jerusalem, Israel; and
| | - Avi Priel
- Cellular and Molecular Pain Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, and
| | | |
Collapse
|
11
|
Udi S, Hinden L, Earley B, Drori A, Reuveni N, Hadar R, Cinar R, Nemirovski A, Tam J. Proximal Tubular Cannabinoid-1 Receptor Regulates Obesity-Induced CKD. J Am Soc Nephrol 2017; 28:3518-3532. [PMID: 28860163 DOI: 10.1681/asn.2016101085] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 06/21/2017] [Indexed: 12/29/2022] Open
Abstract
Obesity-related structural and functional changes in the kidney develop early in the course of obesity and occur independently of hypertension, diabetes, and dyslipidemia. Activating the renal cannabinoid-1 receptor (CB1R) induces nephropathy, whereas CB1R blockade improves kidney function. Whether these effects are mediated via a specific cell type within the kidney remains unknown. Here, we show that specific deletion of CB1R in the renal proximal tubule cells did not protect the mice from obesity, but markedly attenuated the obesity-induced lipid accumulation in the kidney and renal dysfunction, injury, inflammation, and fibrosis. These effects associated with increased activation of liver kinase B1 and the energy sensor AMP-activated protein kinase, as well as enhanced fatty acid β-oxidation. Collectively, these findings indicate that renal proximal tubule cell CB1R contributes to the pathogenesis of obesity-induced renal lipotoxicity and nephropathy by regulating the liver kinase B1/AMP-activated protein kinase signaling pathway.
Collapse
Affiliation(s)
- Shiran Udi
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Liad Hinden
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Brian Earley
- Laboratory of Physiological Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland
| | - Adi Drori
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Noa Reuveni
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rivka Hadar
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Resat Cinar
- Laboratory of Physiological Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland
| | - Alina Nemirovski
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Joseph Tam
- Obesity and Metabolism Laboratory, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel;
| |
Collapse
|
12
|
Tam J, Szanda G, Drori A, Liu Z, Cinar R, Kashiwaya Y, Reitman ML, Kunos G. Peripheral cannabinoid-1 receptor blockade restores hypothalamic leptin signaling. Mol Metab 2017; 6:1113-1125. [PMID: 29031713 PMCID: PMC5641628 DOI: 10.1016/j.molmet.2017.06.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/14/2017] [Accepted: 06/16/2017] [Indexed: 01/31/2023] Open
Abstract
Objective In visceral obesity, an overactive endocannabinoid/CB1 receptor (CB1R) system promotes increased caloric intake and decreases energy expenditure, which are mitigated by global or peripheral CB1R blockade. In mice with diet-induced obesity (DIO), inhibition of food intake by the peripherally restricted CB1R antagonist JD5037 could be attributed to endogenous leptin due to the rapid reversal of hyperleptinemia that maintains leptin resistance, but the signaling pathway engaged by leptin has remained to be determined. Methods We analyzed the hypothalamic circuitry targeted by leptin following chronic treatment of DIO mice with JD5037. Results Leptin treatment or an increase in endogenous leptin following fasting/refeeding induced STAT3 phosphorylation in neurons in the arcuate nucleus (ARC) in lean and JD5037-treated DIO mice, but not in vehicle-treated DIO animals. Co-localization of pSTAT3 in leptin-treated mice was significantly less common with NPY+ than with POMC+ ARC neurons. The hypophagic effect of JD5037 was absent in melanocortin-4 receptor (MC4R) deficient obese mice or DIO mice treated with a MC4R antagonist, but was maintained in NPY−/− mice kept on a high-fat diet. Conclusions Peripheral CB1R blockade in DIO restores sensitivity to endogenous leptin, which elicits hypophagia via the re-activation of melanocortin signaling in the ARC. High-fat diet-induced leptin resistance is reversed by peripheral CB1 blockade. Restored leptin signaling by peripheral CB1 blockade occurs via POMC/MC4R pathway. AgRP/NPY neurons are not required for peripheral CB1 blockade-induced hypophagia in mice with diet-induced obesity.
Collapse
Affiliation(s)
- Joseph Tam
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
| | - Gergő Szanda
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, USA
| | - Adi Drori
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Ziyi Liu
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, USA
| | - Resat Cinar
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, USA
| | - Yoshihiro Kashiwaya
- Laboratory of Metabolic Control, National Institute on Alcohol Abuse and Alcoholism, USA
| | - Marc L Reitman
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - George Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, USA.
| |
Collapse
|
13
|
Abstract
The unfolded protein response (UPR) is an endoplasmic reticulum (ER)-to-nucleus signaling cascade induced in response to ER stress. The UPR aims at restoring homeostasis, but can also induce apoptosis if stress persists. Infection by human and murine cytomegaloviruses (CMVs) provokes ER stress and induces the UPR. However, both CMVs manipulate the UPR to promote its prosurvival activity and delay apoptosis. The underlying mechanisms remain largely unknown. Recently, we demonstrated that MCMV and HCMV encode a late protein to target IRE1 for degradation. However, the importance of its downstream effector, X Box binding protein 1 (XBP-1), has not been directly studied. Here we show that deletion of XBP-1 prior to or early after infection confers a transient delay in viral propagation in fibroblasts that can be overcome by increasing the viral dose. A similar phenotype was demonstrated in peritoneal macrophages. In vivo, acute infection by MCMV is reduced in the absence of XBP-1. Our data indicate that removal of XBP-1 confers a kinetic delay in early stages of MCMV infection and suggest that the late targeting of IRE1 is aimed at inhibiting activities other than the splicing of XBP-1 mRNA.
Collapse
Affiliation(s)
- Adi Drori
- Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Martin Messerle
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Wolfram Brune
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Boaz Tirosh
- Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| |
Collapse
|
14
|
|