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Stark AK, Davenport ECM, Patton DT, Scudamore CL, Vanhaesebroeck B, Veldhoen M, Garden OA, Okkenhaug K. Loss of Phosphatidylinositol 3-Kinase Activity in Regulatory T Cells Leads to Neuronal Inflammation. J Immunol 2020; 205:78-89. [PMID: 32414808 PMCID: PMC7311201 DOI: 10.4049/jimmunol.2000043] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/21/2020] [Indexed: 12/29/2022]
Abstract
Class I PI3K enzymes are critical for the maintenance of effective immunity. In T cells, PI3Kα and PI3Kδ are activated by the TCR and costimulatory receptors, whereas PI3Kγ is activated by G protein-coupled chemokine receptors. PI3Kδ is a key regulator of regulatory T (Treg) cell function. PI3K isoform-selective inhibitors are in development for the treatment of diseases associated with immune dysregulation, including chronic inflammatory conditions, cancer, and autoimmune diseases. Idelalisib (PI3Kδ), alpelisib (PI3Kα), duvelisib (PI3Kδ/γ), and copanlisib (pan-PI3K) have recently been approved for use in cancer treatment. Although effective, these therapies often have severe side effects associated with immune dysregulation and, in particular, loss of Treg cells. Therefore, it is important to gain a better understanding of the relative contribution of different PI3K isoforms under homeostatic and inflammatory conditions. Experimental autoimmune encephalitis is a mouse model of T cell-driven CNS inflammation, in which Treg cells play a key protective role. In this study, we show that PI3Kδ is required to maintain normal Treg cell development and phenotype under homeostatic conditions but that loss of PI3Kδ alone in Treg cells does not lead to autoimmunity. However, combined loss of PI3Kα and PI3Kδ signaling resulted in increased experimental autoimmune encephalitis disease severity. Moreover, mice lacking PI3Kα and PI3Kδ in Treg cells developed spontaneous peripheral nerve inflammation. These results show a key role for PI3K signaling in Treg cell-mediated protection against CNS inflammation.
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MESH Headings
- Animals
- Autoimmunity/genetics
- Class I Phosphatidylinositol 3-Kinases/genetics
- Class I Phosphatidylinositol 3-Kinases/metabolism
- Class Ib Phosphatidylinositol 3-Kinase/genetics
- Class Ib Phosphatidylinositol 3-Kinase/metabolism
- Encephalomyelitis, Autoimmune, Experimental/blood
- Encephalomyelitis, Autoimmune, Experimental/diagnosis
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Female
- Humans
- Male
- Mice
- Mice, Transgenic
- Myelin-Oligodendrocyte Glycoprotein/administration & dosage
- Myelin-Oligodendrocyte Glycoprotein/immunology
- Peptide Fragments/administration & dosage
- Peptide Fragments/immunology
- Peripheral Nerves/immunology
- Peripheral Nerves/pathology
- Severity of Illness Index
- Signal Transduction/genetics
- Signal Transduction/immunology
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
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Affiliation(s)
- Anne-Katrien Stark
- Laboratory of Lymphocyte Signalling and Development, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Elizabeth C M Davenport
- Laboratory of Lymphocyte Signalling and Development, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
- Royal Veterinary College, London NW1 0TU, United Kingdom
| | - Daniel T Patton
- Laboratory of Lymphocyte Signalling and Development, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - Cheryl L Scudamore
- Royal Veterinary College, London NW1 0TU, United Kingdom
- Exepathology, Exmouth EX8 5LQ, United Kingdom
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, London WC1E 6AG, United Kingdom
| | - Marc Veldhoen
- Laboratory of Lymphocyte Signalling and Development, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
- Instituto de Medicina Molecular, Joâo Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisbon, Portugal; and
| | - Oliver A Garden
- Royal Veterinary College, London NW1 0TU, United Kingdom
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Klaus Okkenhaug
- Laboratory of Lymphocyte Signalling and Development, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom;
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
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Walsh ME, Sloane LB, Fischer KE, Austad SN, Richardson A, Van Remmen H. Use of Nerve Conduction Velocity to Assess Peripheral Nerve Health in Aging Mice. J Gerontol A Biol Sci Med Sci 2014; 70:1312-9. [PMID: 25477428 DOI: 10.1093/gerona/glu208] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [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: 07/14/2014] [Accepted: 10/01/2014] [Indexed: 12/13/2022] Open
Abstract
Nerve conduction velocity (NCV), the speed at which electrical signals propagate along peripheral nerves, is used in the clinic to evaluate nerve function in humans. A decline in peripheral nerve function is associated with a number of age-related pathologies. While several studies have shown that NCV declines with age in humans, there is little information on the effect of age on NCV in peripheral nerves in mice. In this study, we evaluated NCV in male and female C57Bl/6 mice ranging from 4 to 32 months of age. We observed a decline in NCV in both male and female mice after 20 months of age. Sex differences were detected in sensory NCV as well as the rate of decline during aging in motor nerves; female mice had slower sensory NCV and a slower age-related decline in motor nerves compared with male mice. We also tested the effect of dietary restriction on NCV in 30-month-old female mice. Dietary restriction prevented the age-related decline in sciatic NCV but not other nerves. Because NCV is clinically relevant to the assessment of nerve function, we recommend that NCV be used to evaluate healthspan in assessing genetic and pharmacological interventions that increase the life span of mice.
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Affiliation(s)
- Michael E Walsh
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Lauren B Sloane
- Department of Biology, State University of New York at Delhi, Delhi, New York
| | - Kathleen E Fischer
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Steven N Austad
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Arlan Richardson
- Oklahoma City VA Medical Center, Oklahoma City, Oklahoma. University of Oklahoma Health Science Center, Oklahoma City, Oklahoma
| | - Holly Van Remmen
- Oklahoma City VA Medical Center, Oklahoma City, Oklahoma. Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma.
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Abstract
Electrophysiological investigations in mice, particularly with altered myelination, require reference data of the nerve conduction velocity (CV). CVs of different fibre groups were determined in the hindlimb of anaesthetized adult mice. Differentiation between afferent and efferent fibres was performed by recording at dorsal roots and stimulating at ventral roots, respectively. Correspondingly, recording or stimulation was performed at peripheral hindlimb nerves. Stimulation was performed with graded strength to differentiate between fibre groups. CVs of the same fibre groups were different in different nerves of the hindlimb. CVs for motor fibres were for the tibial nerve (Tib) 38.5±4.0 m/s (Aγ: 16.7±3.0 m/s), the sural nerve (Sur) 39.3±3.1 m/s (12.0±0.8 m/s) and the common peroneal nerve (Per) 46.7±4.7 m/s (22.2±4.4 m/s). CVs for group I afferents were 47.4±3.1 m/s (Tib), 43.8±3.8 m/s (Sur), 55.2±6.1 m/s (Per) and 42.9±4.3 m/s for the posterior biceps (PB). CVs of higher threshold afferents, presumably muscle and cutaneous, cover a broad range and do not really exhibit nerve specific differences. Ranges are for group II 22-38 m/s, for group III 9-19 m/s, and for group IV 0.8-0.9 m/s. Incontrovertible evidence was found for the presence of motor fibres in the sural nerve. The results are useful as references for further electrophysiological investigations particularly in genetically modified mice with myelination changes.
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Fischer LR, Glass JD. Oxidative stress induced by loss of Cu,Zn-superoxide dismutase (SOD1) or superoxide-generating herbicides causes axonal degeneration in mouse DRG cultures. Acta Neuropathol 2010; 119:249-59. [PMID: 20039174 DOI: 10.1007/s00401-009-0631-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 12/08/2009] [Accepted: 12/18/2009] [Indexed: 12/13/2022]
Abstract
Axonal degeneration is a common pathologic feature in peripheral neuropathy, neurodegenerative disease, and normal aging. Oxidative stress may be an important mechanism of axonal degeneration, but is underrepresented among current experimental models. To test the effects of loss of the antioxidant enzyme Cu,Zn-superoxide dismutase (SOD1) on axon survival, we cultured dorsal root ganglion (DRG) neurons from SOD1 knockout mice. Beginning as early as 48-72 h, we observed striking degeneration of Sod1-/- axons that was prevented by introduction of human SOD1 and was attenuated by antioxidant treatment. To test susceptibility to increased superoxide production, we exposed wild-type DRGs to the redox-cycling herbicides paraquat and diquat (DQ). Dose-dependent axon degeneration was observed, and toxicity of DQ was exacerbated by SOD1 deficiency. MTT staining suggested that DRG axons are more susceptible to injury than their parent cell bodies in both paradigms. Taken together, these data demonstrate susceptibility of DRG axons to oxidative stress-mediated injury due to loss of SOD1 or excess superoxide production. These in vitro models provide a novel means of investigating oxidative stress-mediated injury to axons, to improve our understanding of axonal redox control and dysfunction in peripheral neuropathy.
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Affiliation(s)
- Lindsey R Fischer
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
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Gaubert ML, Sigaudo-Roussel D, Tartas M, Berrut G, Saumet JL, Fromy B. Endothelium-derived hyperpolarizing factor as an in vivo back-up mechanism in the cutaneous microcirculation in old mice. J Physiol 2007; 585:617-26. [PMID: 17932144 DOI: 10.1113/jphysiol.2007.143750] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
There is now strong evidence that an endothelium-derived hyperpolarizing factor (EDHF), other than nitric oxide (NO) or prostaglandin (PG), exists for dilating arteries and arterioles. In vitro studies on isolated vessels pointed out a role for EDHF as a back-up mechanism when the NO pathway is impaired, but there was a lack of in vivo studies showing a functional role for EDHF. Ageing has pronounced effects on vascular function and particularly on endothelium-dependent relaxation, providing a novel situation in which to assess the contributions of EDHF. The purpose of the present study was thus to determine if, in vivo, there was a functional role for EDHF as a back-up mechanism in the cutaneous microcirculation in the ageing process. We investigated in vivo the contribution of each endothelial factor (NO, PG and EDHF) in the cutaneous vasodilatation induced by iontophoretic delivery of acetylcholine and local pressure application in young adult (6-7 months) and old (22-25 months) mice, using pharmacological inhibitors. The cutaneous vasodilator responses induced by acetylcholine and local pressure application were dependent upon NO and PG pathways in young adult mice, whereas they were EDHF-dependent in old mice. EDHF appears to serve as a back-up mechanism when ageing reaches pathological states in terms of the ability for NO and PG to relax cutaneous microvessels, allowing for persistent cutaneous vasodilatator responses in old mice. However, as a back-up mechanism, EDHF did not completely restore cutaneous vasodilatation, since endothelial responses were reduced in old mice compared to young adult mice.
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Affiliation(s)
- Marie Line Gaubert
- Integrative neuro-vascular biology, UMR CNRS 6214-INSERM 771, Medical School, University of Angers, France
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Finkel JC, Besch VG, Hergen A, Kakareka J, Pohida T, Melzer JM, Koziol D, Wesley R, Quezado ZMN. Effects of aging on current vocalization threshold in mice measured by a novel nociception assay. Anesthesiology 2006; 105:360-9. [PMID: 16871071 PMCID: PMC4780048 DOI: 10.1097/00000542-200608000-00020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Age-related changes in nociception have been extensively studied in the past decades. However, it remains unclear whether in addition to the increased incidence of chronic illness, age-related changes in nociception contribute to increased prevalence of pain in the elderly. Although a great deal of evidence suggests that nociception thresholds increase with aging, other studies yield disparate results. The aim of this investigation was to longitudinally determine the effect of aging on nociception. METHODS The authors developed a nociception assay for mice using electrical stimuli at 2,000, 250, and 5 Hz that reportedly stimulate Abeta, Adelta, and C sensory nerve fibers, respectively. A system was designed to automate a method that elicits and detects pain-avoiding behavior in mice. Using a Latin square design, the authors measured current vocalization thresholds serially over the course of mice's life span. RESULTS For 2,000-Hz (Abeta), 250-Hz (Adelta), and 5-Hz (C) electrical stimuli, current vocalization thresholds first decreases and then increases with aging following a U-shaped pattern (P < 0.001). In addition, average current vocalization thresholds at youth and senescence are significantly higher than those at middle age for the 250-Hz (Adelta) and 5-Hz (C fiber) electrical stimulus (P < 0.05). CONCLUSIONS Using a novel and noninjurious nociception assay, the authors showed that over the life span of mice, current vocalization threshold to electrical stimuli changes in a U-shaped pattern. The findings support the notion that age-related changes in nociception are curvilinear, and to properly study and treat pain, the age of subjects should be considered.
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Affiliation(s)
- Julia C Finkel
- Department of Anesthesia and Surgical Services, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD 20892-1512, USA
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Abstract
Nociception was studied in male mice, mostly of the C57BL/6 strain, during continuous or prolonged restriction of caloric intake (60% of ad-libitum) from midlife to senescence (up to 105 weeks). Restricted mice showed fewer licking or biting responses 20-60 min after hind paw injection of 5% formalin at 46 and 70 weeks, but not at 93 weeks. Also, they showed longer response latencies around 46 weeks of age in the 52 degrees C hot-plate test, which partial tail amputation failed to affect, although it did produce at least 2 weeks of chronic neuropathic hypersensitivity in ad libitum controls. Injection of collagen subcutaneously at 36-42 weeks led to chronic hyperalgesia in the DBA/1 but not the C57BL/6 strain, measured weekly by the barely nociceptive 50 degrees C hot-plate test to minimize damage. This collagen-induced arthritic hyperalgesia was then gradually and reversibly blocked during 9-15 weeks of caloric restriction starting at 53-58 weeks. In longitudinal trials on normal mice, performed every 2-4 weeks between 42 and 105 weeks with the 50 degrees C hot-plate, caloric restriction led to altered latencies (higher relative to controls) only in the last 10-20 weeks, perhaps because it delayed the onset of age-related peripheral neuropathies. In conclusion, long-term caloric restriction leads to significant hypoalgesia in pre-senescent mice subjected to above-threshold pain of widely different durations, the effect disappearing at later ages unless spontaneous neuropathies become influential. A reduction in cumulative food intake thus appears to generate antinociceptive signals in adult male mice, perhaps serving specifically to promote riskier behavior during prolonged food shortages.
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Abstract
Functional and structural decline in the neuromuscular system with aging has been recognized as a cause of impairment in physical performance and loss of independence in the elderly. Alterations in spinal cord motor neurones and at the neuromuscular junction have been identified as evidence of denervation in skeletal muscles from aging mammals, including humans. However, the reciprocal influences of neurones on gene expression in muscle and of muscle on age-related neurodegeneration are poorly understood, and, as a result, interventions aimed at delaying or preventing degeneration of the neural component in aging muscle have been largely unsuccessful. The present article discusses the evidence for neural influence on age-related impairments of skeletal muscle, including a role in excitation-contraction uncoupling. The role of nerves in regulating the trophic actions of insulin-like growth factor-1 (IGF-1) and other neurotrophic factors is considered as a novel influence on the effects of aging on the neuromuscular junction. A better understanding of nerve-muscle interactions will allow for more rational interventions in the aging neuromuscular system.
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Affiliation(s)
- Osvaldo Delbono
- Department of Physiology and Pharmacology, Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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