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Wang Y, Gao B, Chen X, Shi X, Li S, Zhang Q, Zhang C, Piao F. Improvement of diabetes-induced spinal cord axon injury with taurine via nerve growth factor-dependent Akt/mTOR pathway. Amino Acids 2024; 56:32. [PMID: 38637413 PMCID: PMC11026277 DOI: 10.1007/s00726-024-03392-8] [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: 08/03/2023] [Accepted: 03/21/2024] [Indexed: 04/20/2024]
Abstract
Diabetic neuropathy (DN) is a common neurological complication caused by diabetes mellitus (DM). Axonal degeneration is generally accepted to be the major pathological change in peripheral DN. Taurine has been evidenced to be neuroprotective in various aspects, but its effect on spinal cord axon injury (SCAI) in DN remains barely reported. This study showed that taurine significantly ameliorated axonal damage of spinal cord (SC), based on morphological and functional analyses, in a rat model of DN induced by streptozotocin (STZ). Taurine was also found to induce neurite outgrowth in cultured cerebral cortex neurons with high glucose exposure. Moreover, taurine up-regulated the expression of nerve growth factor (NGF) and neurite outgrowth relative protein GAP-43 in rat DN model and cultured cortical neurons/VSC4.1 cells. Besides, taurine increased the activating phosphorylation signals of TrkA, Akt, and mTOR. Mechanistically, the neuroprotection by taurine was related to the NGF-pAKT-mTOR axis, because either NGF-neutralizing antibody or Akt or mTOR inhibitors was found to attenuate its beneficial effects. Together, our results demonstrated that taurine promotes spinal cord axon repair in a model of SCAI in STZ-induced diabetic rats, mechanistically associating with the NGF-dependent activation of Akt/mTOR pathway.
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Affiliation(s)
- Yachen Wang
- Stem Cell Clinical Research Center, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, China
| | - Bihu Gao
- Department of Nephrology, Affiliated Zhongshan Hospital of Dalian University, Dalian, 116001, China
- Department of Urology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, China
| | - Xiaochi Chen
- Department of Urology, The First Affiliated Hospital of Dalian Medical University, Dalian, 116011, China
| | - Xiaoxia Shi
- Department of Occupational and Environmental Health, Dalian Medical University, Dalian, 116044, Liaoning, China
| | - Shuangyue Li
- Department of Occupational and Environmental Health, Dalian Medical University, Dalian, 116044, Liaoning, China
| | - Qing Zhang
- Department of Integrative Laboratory, Affiliated Zhongshan Hospital of Dalian University, Dalian, 116001, China.
| | - Cong Zhang
- Department of Nutrition and Food Safety, Dalian Medical University, Dalian, 116044, Liaoning, China.
| | - Fengyuan Piao
- Department of Scientific Research Project, Affiliated Zhongshan Hospital of Dalian University, Dalian, 116001, China.
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Sobrido-Cameán D, Fernández-López B, Pereiro N, Lafuente A, Rodicio MC, Barreiro-Iglesias A. Taurine Promotes Axonal Regeneration after a Complete Spinal Cord Injury in Lampreys. J Neurotrauma 2020; 37:899-903. [DOI: 10.1089/neu.2019.6604] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Daniel Sobrido-Cameán
- Department of Functional Biology, Universidade de Santiago de Compostela, Compostela, Spain
| | - Blanca Fernández-López
- Department of Functional Biology, Universidade de Santiago de Compostela, Compostela, Spain
- Department of Anatomy, University of Helsinki, Helsinki, Finland
| | - Natividad Pereiro
- Laboratory of Toxicology, University of Vigo, Ourense, Spain
- Tragsatec, Madrid, Spain
| | | | - María Celina Rodicio
- Department of Functional Biology, Universidade de Santiago de Compostela, Compostela, Spain
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Oh SM, Bhattarai JP, Han SK, Park SJ. Effects of hypotaurine on substantia gelatinosa neurons of the trigeminal subnucleus caudalis in immature mice. Amino Acids 2016; 48:2843-2853. [PMID: 27573934 DOI: 10.1007/s00726-016-2321-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/22/2016] [Indexed: 12/18/2022]
Abstract
To understand the action and mechanism of hypotaurine, an immediate precursor of taurine, on orofacial nociceptive processing, we examined the direct effects and receptor types involved in hypotaurine-induced responses using the whole-cell patch clamp technique in the substantia gelatinosa (SG) neurons of the trigeminal subnucleus caudalis (Vc) of immature mice. Under the condition of high-chloride pipette solution, hypotaurine elicited inward currents or upward deflections of membrane potential, which increased in a concentration-dependent manner (30-3000 μM) with the EC50 of 663.8 and 337.6 μM, respectively. The responses to 300 µM hypotaurine were reproducible and recovered upon washout. The 300 µM hypotaurine-induced currents were maintained in the presence of TTX, CNQX, and AP5, indicating direct postsynaptic action of hypotaurine on SG neurons. Responses to both low (300 µM) and high (1 or 3 mM) concentrations of hypotaurine were completely and reversibly blocked by the glycine receptor antagonist strychnine (2 µM), but unaffected by the GABAA receptor antagonist gabazine (3 µM) which blocks synaptic GABAA receptors at low concentration. Furthermore, responses to 300 µM hypotaurine and a maximal concentration of glycine (3 mM) were not additive, indicating that hypotaurine and glycine act on the same receptor. Hypotaurine-induced currents were partially antagonized by picrotoxin (50 µM) which blocks homomeric glycine receptors and by bicuculline (10 µM) which is an antagonist of α2 subunit-containing glycine receptors. These results suggest that hypotaurine-induced responses were mediated by glycine receptor activation in the SG neurons and hypotaurine might be used as an effective therapeutics for orofacial pain.
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Affiliation(s)
- Sun Mi Oh
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, 664-14, 1 Ga, Deokjin-Dong, Jeonbuk, Jeonju, 561-756, Republic of Korea
| | - Janardhan Prasad Bhattarai
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, 664-14, 1 Ga, Deokjin-Dong, Jeonbuk, Jeonju, 561-756, Republic of Korea
| | - Seong Kyu Han
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, 664-14, 1 Ga, Deokjin-Dong, Jeonbuk, Jeonju, 561-756, Republic of Korea
| | - Soo Joung Park
- Department of Oral Physiology and Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, 664-14, 1 Ga, Deokjin-Dong, Jeonbuk, Jeonju, 561-756, Republic of Korea.
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Glutaminase immunoreactivity and enzyme activity is increased in the rat dorsal root ganglion following peripheral inflammation. PAIN RESEARCH AND TREATMENT 2011; 2012:414697. [PMID: 22229088 PMCID: PMC3250962 DOI: 10.1155/2012/414697] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/29/2011] [Accepted: 09/08/2011] [Indexed: 01/16/2023]
Abstract
Following inflammation, primary sensory neurons in the dorsal root ganglion (DRG) alter the production of several proteins. Most DRG neurons are glutamatergic, using glutaminase as the enzyme for glutamate production, but little is known about glutaminase following inflammation. In the present study, adjuvant-induced arthritis (AIA) was produced in rats with complete Freund's adjuvant into the hindpaw. At 7 days of AIA, DRG were examined with glutaminase immunohistochemistry, Western blot immunoreactivity, and enzyme activity. Image analysis revealed that glutaminase was elevated most in small-sized neurons (21%) (P < 0.05). Western blot analysis revealed a 19% increase (P < 0.05) in total glutaminase and 21% in mitochondrial glutaminase (P < 0.05). Glutaminase enzyme activity was elevated 29% (P < 0.001) from 2.20 to 2.83 moles/kg/hr. Elevated glutaminase in primary sensory neurons could lead to increased glutamate production in spinal primary afferent terminals contributing to central sensitization or in the peripheral process contributing to peripheral sensitization.
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Bulley S, Shen W. Reciprocal regulation between taurine and glutamate response via Ca2+-dependent pathways in retinal third-order neurons. J Biomed Sci 2010; 17 Suppl 1:S5. [PMID: 20804625 PMCID: PMC2994392 DOI: 10.1186/1423-0127-17-s1-s5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Although taurine and glutamate are the most abundant amino acids conducting neural signals in the central nervous system, the communication between these two neurotransmitters is largely unknown. This study explores the interaction of taurine and glutamate in the retinal third-order neurons. Using specific antibodies, both taurine and taurine transporters were localized in photoreceptors and Off-bipolar cells, glutamatergic neurons in retinas. It is possible that Off-bipolar cells release juxtaposed glutamate and taurine to activate the third-order neurons in retina. The interaction of taurine and glutamate was studied in acutely dissociated third-order neurons in whole-cell patch-clamp recording and Ca2+ imaging. We find that taurine effectively reduces glutamate-induced Ca2+ influx via ionotropic glutamate receptors and voltage-dependent Ca2+ channels in the neurons, and the effect of taurine was selectively inhibited by strychnine and picrotoxin, but not GABA receptor antagonists, although GABA receptors are present in the neurons. A CaMKII inhibitor partially reversed the effect of taurine, suggesting that a Ca2+/calmodulin-dependent pathway is involved in taurine regulation. On the other hand, a rapid influx of Ca2+ through ionotropic glutamate receptors could inhibit the amplitude and kinetics of taurine-elicited currents in the third-order neurons, which could be controlled with intracellular application of BAPTA a fast Ca2+ chelator. This study indicates that taurine is a potential neuromodulator in glutamate transmission. The reciprocal inhibition between taurine and glutamate in the postsynaptic neurons contributes to computation of visual signals in the retinal neurons.
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Affiliation(s)
- Simon Bulley
- College of Biomedical Science, Florida Atlantic University, Boca Raton, FL 33431, USA.
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Nakajima Y, Osuka K, Seki Y, Gupta RC, Hara M, Takayasu M, Wakabayashi T. Taurine reduces inflammatory responses after spinal cord injury. J Neurotrauma 2010; 27:403-10. [PMID: 19831872 DOI: 10.1089/neu.2009.1044] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Taurine has multiple functions in the central nervous system (CNS), serving as an osmoregulator, antioxidant, inhibitory neuromodulator, and regulator of intracellular Ca(2+) flux. Since the role of taurine in traumatic spinal cord injury (SCI) is not fully understood, the present study was conducted with C57 black/6 mice (18-20 g) who underwent severe SCI at the Th-8 level using a weight compression device. Taurine was injected intraperitoneally at doses of 25, 80, 250, and 800 mg/kg within 30 min after SCI. Controls were injected with saline. The contusional cord segments were removed 6 h after SCI, and concentrations of interleukin-6 (IL-6) and myeloperoxidase (MPO) were measured using ELISA kits. Phosphorylation of STAT3, which is activated by IL-6, and expression of inducible cyclooxygenase-2 (COX-2) were also compared between the taurine treatment group (250 mg/kg) and the control group by Western blot analysis. Morphological changes were evaluated with H&E-stained sections. Taurine significantly decreased IL-6 and MPO levels in a dose-dependent manner, significantly reducing the phosphorylation of STAT3 and expression of COX-2 after SCI compared to controls. A reduced accumulation of neutrophils, especially in the subarachnoid spaces, and secondary degenerative changes in gray matter were also noted, and motor disturbances were significantly attenuated with taurine treatment (250 mg/kg). These findings indicate that taurine has anti-inflammatory effects against SCI, and may play a neuroprotective role against secondary damage, and thus it may have therapeutic potential.
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Affiliation(s)
- Yasuhiro Nakajima
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, Aichi, Japan
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Benton RL, Woock JP, Gozal E, Hetman M, Whittemore SR. Intraspinal application of endothelin results in focal ischemic injury of spinal gray matter and restricts the differentiation of engrafted neural stem cells. Neurochem Res 2006; 30:809-23. [PMID: 16187216 DOI: 10.1007/s11064-005-6875-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2005] [Indexed: 10/25/2022]
Abstract
Previous data have shown that pluripotent stem cells engrafted into the contused spinal cord differentiate only along an astrocytic lineage. The unknown restrictive cues appear to be quite rigid as even neuronal-restricted precursors fail to differentiate to the mature potential they exhibit in vitro after similar grafting into the contused spinal cord. It has been hypothesized that this potent lineage restriction is, in part, the result of the significant loss of both gray and white matter observed following spinal contusion, which elicits a massive acute inflammatory response and is manifested chronically by dramatic cystic cavitation. To evaluate the gray matter component, we developed a clinically relevant model of focal gray matter ischemic injury using the potent vasoconstrictor endothelin (ET-1) and characterized the differentiation of pluripotent stem cells transplanted into this atraumatic vascular SCI. Results demonstrate that low dose ET-1 microinjection into cervical spinal gray matter results in an inflammatory response that is temporally comparable to that observed following traumatic SCI, as well as chronic gray matter loss, but without significant cystic cavitation or white matter degeneration. However, despite the preservation of host spinal parenchyma, no elaboration of neuronal phenotypes was observed from engrafted stem or precursor cells. These results suggest that a common pathologic component responsible for this lineage restriction exists between contusive SCI and ET-1 mediated focal ischemic SCI.
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Affiliation(s)
- Richard L Benton
- Kentucky Spinal Cord Injury Research Center (KSCIRC), 511 South Floyd Street, MDR 616, Louisville, KY 40292, USA
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Benton RL, Whittemore SR. VEGF165 therapy exacerbates secondary damage following spinal cord injury. Neurochem Res 2004; 28:1693-703. [PMID: 14584823 DOI: 10.1023/a:1026013106016] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vascular endothelial growth factor (VEGF) demonstrates potent and well-characterized effects on endothelial cytoprotection and angiogenesis. In an attempt to preserve spinal microvasculature and prolong the endogenous neovascular response observed transiently following experimental spinal cord injury (SCI), exogenous recombinant human VEGF (rhVEGF165) was injected into the injured rat spinal cord. Adult female Fischer 344 rats were subjected to moderate SCI (12.5 g-cm) using the NYU impactor. At 72 h after injury, animals were randomly assigned to three experimental groups receiving no microinjection or injection of saline or saline containing 2 microg of rhVEGF165. Acutely, VEGF injection resulted in significant microvascular permeability and infiltration of leukocytes into spinal cord parenchyma. 6 weeks postinjection, no significant differences were observed in most measures of microvascular architecture following VEGF treatment, but analysis of histopathology in spinal cord tissue revealed profound exacerbation of lesion volume. These results support the idea that intraparenchymal application of the proangiogenic factor VEGF may exacerbate SCI, likely through its effect on vessel permeability.
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Affiliation(s)
- Richard L Benton
- The Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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Kipnis J, Nevo U, Panikashvili D, Alexandrovich A, Yoles E, Akselrod S, Shohami E, Schwartz M. Therapeutic vaccination for closed head injury. J Neurotrauma 2003; 20:559-69. [PMID: 12906740 DOI: 10.1089/089771503767168483] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Closed head injury often has a devastating outcome, partly because the insult, like other injuries to the central nervous system (CNS), triggers self-destructive processes. During studies of the response to other CNS insults, it was unexpectedly discovered that the immune system, if well controlled, provides protection against self-destructive activities. Here we show that in mice with closed head injury, the immune system plays a key role in the spontaneous recovery. Strain-related differences were observed in the ability to harness a T cell-dependent protective mechanism against the effects of the injury. We further show that the trauma-induced deficit could be reduced, both functionally and anatomically, by post-traumatic vaccination with Cop-1, a synthetic copolymer used to treat patients with multiple sclerosis and found (using a different treatment protocol) to effectively counteract the loss of neurons caused by axonal injury or glutamate-induced toxicity. We suggest that a compound such as Cop-1 can be safely developed as a therapeutic vaccine to boost the body's immune repair mechanisms, thereby providing multifactorial protection against the consequences of brain trauma.
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Affiliation(s)
- Jonathan Kipnis
- Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel
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Obrosova IG. How does glucose generate oxidative stress in peripheral nerve? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 50:3-35. [PMID: 12198815 DOI: 10.1016/s0074-7742(02)50071-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Diabetes-associated oxidative stress is clearly manifest in peripheral nerve, dorsal root, and sympathetic ganglia of the peripheral nervous system and endothelial cells and is implicated in nerve blood flow and conduction deficits, impaired neurotrophic support, changes in signal transduction and metabolism, and morphological abnormalities characteristic of peripheral diabetic neuropathy (diabetic peripheral neuropathy). Hyperglycemia has a key role in oxidative stress in diabetic nerve, whereas the contribution of other factors, such as endoneurial hypoxia, transition metal imbalance, and hyperlipidemia, has not been rigorously proven. It has been suggested that oxidative stress, particularly mitochondrial superoxide production, is responsible for sorbitol pathway hyperactivity, nonenzymatic glycation/glycooxidation, and activation of protein kinase C. However, this concept is not supported by in vivo studies demonstrating the lack of any inhibition of the sorbitol pathway activity in peripheral nerve, retina, and lens by antioxidants, including potent superoxide scavengers. Its has been also hypothesized that aldose reductase (AR) detoxifies lipid peroxidation products, and therefore, the enzyme inhibition in diabetes is detrimental rather than benefical. However, the role for AR in lipid peroxdation product metabolism has never been demonstrated in vivo, and the effects of aldose reductase inhibitors and antioxidants on diabetic peripheral neuropathy are unidirectional, i.e., both classes of agents prevent and correct functional, metabolic, neurotrophic, and morphological changes in diabetic nerve. Growing evidence indicates that AR has a key role in oxidative stress in the peripheral nerve and contributes to superoxide production by the vascular endothelium. The potential mechanisms of this phenonmenon are discussed.
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Affiliation(s)
- Irina G Obrosova
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA
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