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Lu G, Xiao S, Meng F, Zhang L, Chang Y, Zhao J, Gao N, Su W, Guo X, Liu Y, Li C, Tang W, Zou L, Yu S, Liu R. AMPK activation attenuates central sensitization in a recurrent nitroglycerin-induced chronic migraine mouse model by promoting microglial M2-type polarization. J Headache Pain 2024; 25:29. [PMID: 38454376 PMCID: PMC10921743 DOI: 10.1186/s10194-024-01739-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/27/2024] [Indexed: 03/09/2024] Open
Abstract
BACKGROUND Energy metabolism disorders and neurogenic inflammation play important roles in the central sensitization to chronic migraine (CM). AMP-activated protein kinase (AMPK) is an intracellular energy sensor, and its activation regulates inflammation and reduces neuropathic pain. However, studies on the involvement of AMPK in the regulation of CM are currently lacking. Therefore, this study aimed to explore the mechanism underlying the involvement of AMPK in the central sensitization to CM. METHODS Mice with recurrent nitroglycerin (NTG)-induced CM were used to detect the expression of AMPK protein in the trigeminal nucleus caudalis (TNC). Following intraperitoneal injection of the AMPK activator 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) and inhibitor compound C, the mechanical pain threshold, activity level, and pain-like behaviors in the mice were measured. The expression of calcitonin gene-related peptide (CGRP) and cytokines, M1/M2 microglia, and NF-κB pathway activation were detected after the intervention. RESULTS Repeated NTG injections resulted in a gradual decrease in AMPK protein expression, and the negative regulation of AMPK by increased ubiquitin-like plant homeodomain and RING finger domain 1 (UHRF1) expression may counteract AMPK activation by increasing ADP/ATP. AICAR can reduce the hyperalgesia and pain-like behaviors of CM mice, improve the activity of mice, reduce the expression of CGRP, IL-1β, IL-6, and TNF-α in the TNC region, and increase the expression of IL-4 and IL-10. Moreover, AMPK in TNC was mainly located in microglia. AICAR could reduce the expression of inducible NO synthase (iNOS) in M1 microglia and increase the expression of Arginase 1 (Arg1) in M2 microglia by inhibiting the activation of NF-κB pathway. CONCLUSIONS AMPK was involved in the central sensitization of CM, and the activation of AMPK reduced neuroinflammation in NTG-induced CM mice. AMPK may provide new insights into interventions for energy metabolism disorders and neurogenic inflammation in migraine.
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Affiliation(s)
- Guangshuang Lu
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
- Department of Pediatrics, The Lu'an Hospital Affiliated to Anhui Medical University, The Lu'an People's Hospital, Lu'an, China
| | - Shaobo Xiao
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Fanchao Meng
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Leyi Zhang
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Yan Chang
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Jinjing Zhao
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Nan Gao
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
- School of Medicine, Nankai University, Tianjin, 300071, China
| | - Wenjie Su
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Xinghao Guo
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Yingyuan Liu
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Chenhao Li
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Wenjing Tang
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Liping Zou
- Medical School of Chinese PLA, Beijing, 100853, China
- Department of Pediatrics, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China
| | - Shengyuan Yu
- Medical School of Chinese PLA, Beijing, 100853, China.
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China.
| | - Ruozhuo Liu
- Medical School of Chinese PLA, Beijing, 100853, China.
- Department of Neurology, International Headache Center, The First Medical Center of Chinese PLA General Hospital, Fuxing Road 28, Haidian District, Beijing, 100853, China.
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Song Y, Wu Z, Zhao P. The effects of metformin in the treatment of osteoarthritis: Current perspectives. Front Pharmacol 2022; 13:952560. [PMID: 36081941 PMCID: PMC9445495 DOI: 10.3389/fphar.2022.952560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/27/2022] [Indexed: 02/04/2023] Open
Abstract
Osteoarthritis is a chronic and irreversible disease of the locomotor system which is closely associated with advancing age. Pain and limited mobility frequently affect the quality of life in middle-aged and older adults. With a global population of more than 350 million, osteoarthritis is becoming a health threat alongside cancer and cardiovascular disease. It is challenging to find effective treatments to promote cartilage repair and slow down disease progression. Metformin is the first-line drug for patients with type 2 diabetes, and current perspectives suggest that it cannot only lower glucose but also has anti-inflammatory and anti-aging properties. Experimental studies applying metformin for the treatment of osteoarthritis have received much attention in recent years. In our review, we first presented the history of metformin and the current status of osteoarthritis, followed by a brief review of the mechanism that metformin acts, involving AMPK-dependent and non-dependent pathways. Moreover, we concluded that metformin may be beneficial in the treatment of osteoarthritis by inhibiting inflammation, modulating autophagy, antagonizing oxidative stress, and reducing pain levels. Finally, we analyzed the relevant evidence from animal and human studies. The potential of metformin for the treatment of osteoarthritis deserves to be further explored.
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Zhang X, Song T, Zhao M, Tao X, Zhang B, Sun C, Wang P, Wang K, Zhao L. Sirtuin 2 Alleviates Chronic Neuropathic Pain by Suppressing Ferroptosis in Rats. Front Pharmacol 2022; 13:827016. [PMID: 35401208 PMCID: PMC8984153 DOI: 10.3389/fphar.2022.827016] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Neuropathic pain (NP) is chronic and associated with poor effects of general analgesia. It affects patients’ health and quality of life. The apoptotic process of lipid peroxidation caused by iron overload is called ferroptosis, which may be associated with nervous system disease. A recent study has found that sirtuin 2 (SIRT2) achieves a neuroprotective effect by suppressing ferroptosis. Herein, we aimed to examine whether SIRT2 regulated spared nerve injury (SNI)-induced NP by suppressing ferroptosis in rats. A rat model of NP was induced in adult male Sprague-Dawley rats weighing 200–250 g. Mechanical allodynia was observed from the first day after SNI and continued for 14 days. Compared with age-matched control rats, the expression of SIRT2 and ferroportin 1 (FPN1) decreased in the L4-6 spinal cord of the SNI-induced NP rats. In addition, we observed that the levels of both iron and anti-acyl-coenzyme A synthetase long-chain family member 4 (ACSL4) were significantly increased in the spinal cord after SNI, while the expression of glutathione peroxidase 4 (GPX4) was decreased. Furthermore, an intrathecal injection of SIRT2 overexpressed recombinant adenovirus, which upregulated the expression of SIRT2, attenuated mechanical allodynia, enhanced the level of FPN1, inhibited intracellular iron accumulation, and reduced oxidant stress levels, thereby reversing the changes to ACSL4 and GPX4 expression in the SNI rats. This evidence suggests that SIRT2-targeted therapeutics may help relieve the symptoms of chronic NP.
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Wang S, Dai Y. Roles of AMPK and Its Downstream Signals in Pain Regulation. Life (Basel) 2021; 11:life11080836. [PMID: 34440581 PMCID: PMC8401922 DOI: 10.3390/life11080836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/06/2021] [Accepted: 08/12/2021] [Indexed: 12/20/2022] Open
Abstract
Pain is an unpleasant sensory and emotional state that decreases quality of life. A metabolic sensor, adenosine monophosphate-activated protein kinase (AMPK), which is ubiquitously expressed in mammalian cells, has recently attracted interest as a new target of pain research. Abnormal AMPK expression and function in the peripheral and central nervous systems are associated with various types of pain. AMPK and its downstream kinases participate in the regulation of neuron excitability, neuroinflammation and axonal and myelin regeneration. Numerous AMPK activators have reduced pain behavior in animal models. The current understanding of pain has been deepened by AMPK research, but certain issues, such as the interactions of AMPK at each step of pain regulation, await further investigation. This review examines the roles of AMPK and its downstream kinases in neurons and non-neuronal cells, as well as their contribution to pain regulation.
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Affiliation(s)
- Shenglan Wang
- School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing 100029, China
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Japan
- Correspondence: (S.W.); (Y.D.); Tel.: +86-10-53912197 (S.W.); +81-78-304-3147 (Y.D.)
| | - Yi Dai
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Japan
- Traditional Medicine Research Center, Chinese Medicine Confucius Institute, Hyogo College of Medicine, Kobe 663-8501, Japan
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, Nishinomiya 663-8501, Japan
- Correspondence: (S.W.); (Y.D.); Tel.: +86-10-53912197 (S.W.); +81-78-304-3147 (Y.D.)
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Diet, body weight and pain susceptibility - A systematic review of preclinical studies. NEUROBIOLOGY OF PAIN 2021; 10:100066. [PMID: 34195483 PMCID: PMC8237587 DOI: 10.1016/j.ynpai.2021.100066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/26/2021] [Accepted: 06/11/2021] [Indexed: 02/07/2023]
Abstract
Obesity has been associated with increased susceptibility to chronic pain. Dietary and genetic models of obesity have been used to study this association. Allodynia is a common finding but alterations in nociception were inconsistent across studies. In subacute/chronic models, nocifencive behaviors were increased and/or sustained. Reviewed studies are overall consonant with the clinical literature.
Obesity has been associated with increased chronic pain susceptibility but causes are unclear. In this review, we systematize and analyze pain outcomes in rodent models of obesity as these can be important tools for mechanistic studies. Studies were identified using MEDLINE/PubMed and Scopus databases using the following search query: (((pain) OR (nociception)) AND (obesity)) AND (rat OR (mouse) OR (rodent))). From each eligible record we extracted the following data: species, strain, sex, pain/obesity model and main behavioral readouts. Out of 695 records 33 were selected for inclusion. 27 studies assessed nociception/acute pain and 17 studies assessed subacute or chronic pain. Overall genetic and dietary models overlapped in pain-related outcomes. Most acute pain studies reported either decreased or unaltered responses to noxious painful stimuli. However, decreased thresholds to mechanical innocuous stimuli, i.e. allodynia, were frequently reported. In most studies using subacute and chronic pain models, namely of subcutaneous inflammation, arthritis and perineural inflammation, decreased thresholds and/or prolonged pain manifestations were reported in obesity models. Strain comparisons and longitudinal observations indicate that genetic factors and the time course of the pathology might account for some of the discrepancies observed across studies. Two studies reported increased pain in animals subjected to high fat diet in the absence of weight gain. Pain-related outcomes in experimental models and clinical obesity are aligned indicating that the rodent can be an useful tool to study the interplay between diet, obesity and pain. In both cases weight gain might represent only a minor contribution to abnormal pain manifestation.
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Sex-dependent effects of forced exercise in the body composition of adolescent rats. Sci Rep 2021; 11:10154. [PMID: 33980961 PMCID: PMC8115159 DOI: 10.1038/s41598-021-89584-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/26/2021] [Indexed: 12/14/2022] Open
Abstract
Determining the body composition during adolescence can predict diseases such as obesity, diabetes, and metabolic syndromes later in life; and physical activity became an effective way to restore changes in body composition. However, current available literature assessing the body composition before, during and after adolescence in female and male rodents by in vivo techniques is scarce. Thus, by using computerized tomography, we aimed to define the baseline of the weight and body composition during the adolescence and young adulthood of female and male Sprague-Dawley rats (on P30, P60 and P90) under standard diet. Then, we determined the effect of 18 days of forced exercise on the body weight and composition during the early adolescence (P27-45). The highest percentual increments in weight, body volume and relative adipose contents occurred during the female and male adolescence. Forced running during the early adolescence decreased weight, body volume and relative adipose delta and increment values in males only. The adolescence of rats is a period of drastic body composition changes, where exercise interventions have sex-dependent effects. These results support a model that could open new research windows in the field of adolescent obesity.
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Zhao M, Zhang X, Tao X, Zhang B, Sun C, Wang P, Song T. Sirt2 in the Spinal Cord Regulates Chronic Neuropathic Pain Through Nrf2-Mediated Oxidative Stress Pathway in Rats. Front Pharmacol 2021; 12:646477. [PMID: 33897435 PMCID: PMC8063033 DOI: 10.3389/fphar.2021.646477] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 02/24/2021] [Indexed: 01/06/2023] Open
Abstract
Reduction in Nrf2-mediated antioxidant response in the central nervous system plays an important role in the development and maintenance of neuropathic pain (NP). However, the mechanisms regulating Nrf2 activity in NP remain unclear. A recent in vitro study revealed that Sirt2, a member of the sirtuin family of proteins, affects antioxidant capacity by modulating Nrf2 activity. Here we examined whether central Sirt2 regulates NP through Nrf2-mediated oxidative stress pathway. In a rat model of spared nerve injury (SNI)-induced NP, mechanical allodynia and thermal hyperalgesia were observed on day 1 and up to day 14 post-SNI. The expression of Sirt2, Nrf2 and its target gene NQO1 in the spinal cord in SNI rats, compared with sham rats, was significantly decreased from day 7 and remained lower until the end of the experiment (day 14). The mechanical allodynia and thermal hyperalgesia in SNI rats were ameliorated by intrathecal injection of Nrf2 agonist tBHQ, which normalized expression of Nrf2 and NQO1 and reversed SNI-induced decrease in antioxidant enzyme superoxide dismutase (SOD) and increase in oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the spinal cord. Moreover, intrathecal injection of a recombinant adenovirus expressing Sirt2 (Ad-Sirt2) that upregulated expression of Sirt2, restored expression of Nrf2 and NQO1 and attenuated oxidative stress in the spinal cord, leading to improvement of thermal hyperalgesia and mechanical allodynia in SNI rats. These findings suggest that peripheral nerve injury downregulates Sirt2 expression in the spinal cord, which inhibits Nrf2 activity, leading to increased oxidative stress and the development of chronic NP.
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Affiliation(s)
- Mengnan Zhao
- Department of Pain Medicine, The First Hospital of China Medical University, Shenyang, China
| | - Xiaojiao Zhang
- Department of Pain Medicine, The First Hospital of China Medical University, Shenyang, China
| | - Xueshu Tao
- Department of Pain Medicine, The First Hospital of China Medical University, Shenyang, China
| | - Bohan Zhang
- Department of Pain Medicine, The First Hospital of China Medical University, Shenyang, China
| | - Cong Sun
- Department of Pain Medicine, The First Hospital of China Medical University, Shenyang, China
| | - Pinying Wang
- Department of Pain Medicine, The First Hospital of China Medical University, Shenyang, China
| | - Tao Song
- Department of Pain Medicine, The First Hospital of China Medical University, Shenyang, China
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Li J, Liu HQ, Li XB, Yu WJ, Wang T. Function of Adenosine 2A Receptor in High-Fat Diet-Induced Peripheral Neuropathy. J Diabetes Res 2020; 2020:7856503. [PMID: 32566683 PMCID: PMC7267854 DOI: 10.1155/2020/7856503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/27/2020] [Accepted: 04/13/2020] [Indexed: 12/18/2022] Open
Abstract
Peripheral diabetic neuropathy (DPN) is a complication observed in up to half of all patients with type 2 diabetes. DPN has also been shown to be associated with obesity. High-fat diet (HFD) affects glucose metabolism, and the impaired glucose tolerance can lead to type 2 diabetes. There is evidence to suggest a role of adenosine 2A receptors (A2ARs) and semaphorin 3A (Sema3a) signaling in DPN. The link between the expression of Sema3a and A2AR in DPN was hypothesized, but the underlying mechanisms remain poorly understood. In this study, we investigated the regulation of Sema3a by A2AR in the spinal cord and the functional implications thereof in DPN. We examined the expression of A2ARs and Sema3a, as well as Neuropilin 1 and Plexin A, the coreceptors of Sema3a, in the dorsal horn of the lumbar spinal cord of an animal model with HFD-induced diabetes. Our results demonstrate that HFD dysregulates the A2AR-mediated Sema3a expression, with functional implications for the type 2 diabetes-induced peripheral neuropathy. These observations could stimulate clinical studies to improve our understanding on the subject.
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MESH Headings
- Animals
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Diabetic Neuropathies/etiology
- Diabetic Neuropathies/metabolism
- Diabetic Neuropathies/pathology
- Diet, High-Fat
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Nerve Fibers/metabolism
- Nerve Fibers/pathology
- Receptor, Adenosine A2A/physiology
- Semaphorin-3A/metabolism
- Spinal Cord/metabolism
- Spinal Cord/pathology
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Affiliation(s)
- Ji Li
- Department of Anesthesiology, The First Hospital of Jilin University, Changchun, China
| | - Huan-Qiu Liu
- Department of Anesthesiology, The First Hospital of Jilin University, Changchun, China
| | - Xin-Bai Li
- Department of Anesthesiology, The First Hospital of Jilin University, Changchun, China
| | - Wen-Jun Yu
- Department of Hand Surgery, The First Hospital of Jilin University, Changchun, China
| | - Tao Wang
- Department of Hand Surgery, The First Hospital of Jilin University, Changchun, China
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Hasib A, Hennayake CK, Bracy DP, Bugler-Lamb AR, Lantier L, Khan F, Ashford MLJ, McCrimmon RJ, Wasserman DH, Kang L. CD44 contributes to hyaluronan-mediated insulin resistance in skeletal muscle of high-fat-fed C57BL/6 mice. Am J Physiol Endocrinol Metab 2019; 317:E973-E983. [PMID: 31550181 PMCID: PMC6957377 DOI: 10.1152/ajpendo.00215.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Extracellular matrix hyaluronan is increased in skeletal muscle of high-fat-fed insulin-resistant mice, and reduction of hyaluronan by PEGPH20 hyaluronidase ameliorates diet-induced insulin resistance (IR). CD44, the main hyaluronan receptor, is positively correlated with type 2 diabetes. This study determines the role of CD44 in skeletal muscle IR. Global CD44-deficient (cd44-/-) mice and wild-type littermates (cd44+/+) were fed a chow diet or 60% high-fat diet for 16 wk. High-fat-fed cd44-/- mice were also treated with PEGPH20 to evaluate its CD44-dependent action. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp (ICv). High-fat feeding increased muscle CD44 protein expression. In the absence of differences in body weight and composition, despite lower clamp insulin during ICv, the cd44-/- mice had sustained glucose infusion rate (GIR) regardless of diet. High-fat diet-induced muscle IR as evidenced by decreased muscle glucose uptake (Rg) was exhibited in cd44+/+ mice but absent in cd44-/- mice. Moreover, gastrocnemius Rg remained unchanged between genotypes on chow diet but was increased in high-fat-fed cd44-/- compared with cd44+/+ when normalized to clamp insulin concentrations. Ameliorated muscle IR in high-fat-fed cd44-/- mice was associated with increased vascularization. In contrast to previously observed increases in wild-type mice, PEGPH20 treatment in high-fat-fed cd44-/- mice did not change GIR or muscle Rg during ICv, suggesting a CD44-dependent action. In conclusion, genetic CD44 deletion improves muscle IR, and the beneficial effects of PEGPH20 are CD44-dependent. These results suggest a critical role of CD44 in promoting hyaluronan-mediated muscle IR, therefore representing a potential therapeutic target for diabetes.
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Affiliation(s)
- Annie Hasib
- Division of Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom
| | - Chandani K Hennayake
- Division of Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom
| | - Deanna P Bracy
- Department of Molecular Physiology and Biophysics and Mouse Metabolic Phenotyping Centre, Vanderbilt University, Nashville, Tennessee
| | - Aimée R Bugler-Lamb
- Division of Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom
| | - Louise Lantier
- Department of Molecular Physiology and Biophysics and Mouse Metabolic Phenotyping Centre, Vanderbilt University, Nashville, Tennessee
| | - Faisel Khan
- Division of Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom
| | - Michael L J Ashford
- Division of Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom
| | - Rory J McCrimmon
- Division of Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics and Mouse Metabolic Phenotyping Centre, Vanderbilt University, Nashville, Tennessee
| | - Li Kang
- Division of Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom
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Infiltration of Blood-Derived Macrophages Contributes to the Development of Diabetic Neuropathy. J Immunol Res 2019; 2019:7597382. [PMID: 31534976 PMCID: PMC6732633 DOI: 10.1155/2019/7597382] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/30/2019] [Accepted: 07/16/2019] [Indexed: 11/18/2022] Open
Abstract
Background and Objective Diabetic neuropathic pain (DNP) is a common complication associated with diabetes. Currently, its underlying pathomechanism remains unknown. Studies have revealed that the recruitment of blood monocyte-derived macrophages (MDMs) to the spinal cord plays a pivotal role in different models of central nervous system injury. Therefore, the present study aimed at exploring the infiltration and function of MDMs in DNP using a mice model. Methods Diabetes was induced using streptozotocin in male A/J mice. Mechanical withdrawal thresholds were measured weekly to characterize neuropathy phenotype. Quantitative analysis of CD11b was performed and visualized by immunofluorescence. Spinal cord cells were isolated from myelin and debris by Percoll gradient. Flow cytometry was used to label CD11b and CD45 antibodies to differentiate MDMs (CD45highCD11b+) from resident microglia (CD45lowCD11b+). Mice were injected with clodronate liposomes to investigate the role of MDMs in DNP. The successful depletion of monocytes was determined by flow cytometry. Results The DNP mice model was successfully established. Compared with nondiabetic mice, diabetic mice displayed a markedly higher level of CD11b immunofluorescence in the spinal cord. The number of CD11b-positive microglia/macrophages gradually increased over the 28 days of testing after STZ injection, and a significant increase was observed on Day 14 (P < 0.01) and 28 (P < 0.01). Further analysis by flow cytometry showed that the infiltration of peripheral macrophages began to increase in 2 weeks (P < 0.001) and reached a maximum at 4 weeks (P < 0.001) post-STZ injection compared to the control. The depletion of MDMs by clodronate liposomes alleviated diabetes-induced tactile allodynia (P < 0.05) and reduced the infiltration of MDMs (P < 0.001) as well as the expression of IL-1β and TNF-α in the spinal cord (P < 0.05). Conclusions The infiltration of blood MDMs in the spinal cord may promote the development of painful neuropathy in diabetes.
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