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Fox RI, Fox CM, Gottenberg JE, Dörner T. Treatment of Sjögren's syndrome: current therapy and future directions. Rheumatology (Oxford) 2021; 60:2066-2074. [PMID: 31034046 DOI: 10.1093/rheumatology/kez142] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 03/08/2019] [Indexed: 12/12/2022] Open
Abstract
SS is usually described as having severe fatigue, dryness, diffuse pain, glandular swelling, and various extraglandular (systemic) manifestations. Clinical trials have generally failed because the vast majority of enrolled patients had no extraglandular manifestations at the time of enrolment but suffered from fatigue, dryness and pain that did not significantly respond to the study medication. A number of hypotheses on the pathogenesis of pSS have been put forward, including disturbances of innate and adaptive immunity as well as abnormalities of the interface between immune disorders and the neuro-endocrine system related to lacrimal and secretory gland dysfunction. Thus, future therapies must be designed for improvement of the symptoms of dry eyes and dry mouth, extraglandular disease, and fatigue and cognitive deficits. Given the inadequacies and limitations of current treatment options, we suggest that innovative directions involving interactions with neuroscientists and neuropsychiatrists together or combined with new immune targeting may be hold promise for better treating pSS.
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Affiliation(s)
- Robert I Fox
- Rheumatology Clinic, Scripps Memorial Hospital and Research Foundation, La Jolla, CA
| | - Carla M Fox
- Rheumatology Clinic, Scripps Memorial Hospital and Research Foundation, La Jolla, CA
| | - Jacques Eric Gottenberg
- Strasbourg University Hospital, National Center for Rare Systemic Autoimmune Diseases, Strasbourg, France
| | - Thomas Dörner
- Department of Medicine/Rheumatology and Clinical Immunology, Charite Universitätsmedizin Berlin & DRFZ Berlin, Berlin, Germany
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Masli S, Dartt DA. Mouse Models of Sjögren's Syndrome with Ocular Surface Disease. Int J Mol Sci 2020; 21:ijms21239112. [PMID: 33266081 PMCID: PMC7730359 DOI: 10.3390/ijms21239112] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/28/2020] [Accepted: 11/28/2020] [Indexed: 12/12/2022] Open
Abstract
Sjögren’s syndrome (SS) is a systemic rheumatic disease that predominantly affects salivary and lacrimal glands resulting in oral and ocular dryness, respectively, referred to as sicca symptoms. The clinical presentation of ocular dryness includes keratoconjunctivitis sicca (KCS), resulting from the inflammatory damage to the ocular surface tissues of cornea and conjunctiva. The diagnostic evaluation of KCS is a critical component of the classification criteria used by clinicians worldwide to confirm SS diagnosis. Therapeutic management of SS requires both topical and systemic treatments. Several mouse models of SS have contributed to our current understanding of immunopathologic mechanisms underlying the disease. This information also helps develop novel therapeutic interventions. Although these models address glandular aspects of SS pathology, their impact on ocular surface tissues is addressed only in a few models such as thrombospondin (TSP)-1 deficient, C57BL/6.NOD.Aec1Aec2, NOD.H2b, NOD.Aire KO, and IL-2Rα (CD25) KO mice. While corneal and/or conjunctival damage is reported in most of these models, the characteristic SS specific autoantibodies are only reported in the TSP-1 deficient mouse model, which is also validated as a preclinical model. This review summarizes valuable insights provided by investigations on the ocular spectrum of the SS pathology in these models.
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Affiliation(s)
- Sharmila Masli
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA 02118, USA
- Correspondence: (S.M.); (D.A.D.); Tel.: +1-617-358-2195 (S.M.); +1-617-912-0272 (D.A.D.)
| | - Darlene A. Dartt
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
- Correspondence: (S.M.); (D.A.D.); Tel.: +1-617-358-2195 (S.M.); +1-617-912-0272 (D.A.D.)
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Zyrianova T, Basova LV, Makarenkova H. Isolation of Myoepithelial Cells from Adult Murine Lacrimal and Submandibular Glands. J Vis Exp 2019. [PMID: 31259892 DOI: 10.3791/59602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The lacrimal gland (LG) is an exocrine tubuloacinar gland that secretes an aqueous layer of tear film. The LG epithelial tree is comprised of acinar, ductal epithelial, and myoepithelial cells (MECs). MECs express alpha smooth muscle actin (αSMA) and have a contractile function. They are found in multiple glandular organs and are of ectodermal origin. In addition, the LG contains SMA+ vascular smooth muscle cells of endodermal origin called pericytes: contractile cells that envelop the surface of vascular tubes. A new protocol allows us to isolate both MECs and pericytes from adult murine LGs and submandibular glands (SMGs). The protocol is based on the genetic labeling of MECs and pericytes using the SMACreErt2/+:Rosa26-TdTomatofl/fl mouse strain, followed by preparation of the LG single-cell suspension for fluorescence activated cell sorting (FACS). The protocol allows for the separation of these two cell populations of different origins based on the expression of the epithelial cell adhesion molecule (EpCAM) by MECs, whereas pericytes do not express EpCAM. Isolated cells could be used for cell cultivation or gene expression analysis.
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Affiliation(s)
| | - Liana V Basova
- Department of Molecular Medicine, The Scripps Research Institute
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Bhattacharya S, García-Posadas L, Hodges RR, Makarenkova HP, Masli S, Dartt DA. Alteration in nerves and neurotransmitter stimulation of lacrimal gland secretion in the TSP-1 -/- mouse model of aqueous deficiency dry eye. Mucosal Immunol 2018; 11:1138-1148. [PMID: 29445135 PMCID: PMC6030454 DOI: 10.1038/s41385-018-0002-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 01/02/2018] [Accepted: 01/04/2018] [Indexed: 02/04/2023]
Abstract
The purpose of this study is to determine neural, vascular, protein secretion, and cellular signaling changes with disease progression in lacrimal glands of the thrombospondin-1-/- (TSP-1-/-) mouse model of dry eye compared to C57BL/6 wild-type (WT) mice. Neural innervation was reduced in TSP-1-/- lacrimal glands compared to WT controls, whereas the number of blood vessels was increased. Intracellular Ca2+ stores and the amount of lysosomes, mitochondria, and secretory granules, but not the endoplasmic reticulum, were reduced in TSP-1-/- compared to WT acini at 12 weeks of age. Ex vivo high KCl-evoked secretion was decreased in TSP-1-/- compared to WT lacrimal gland tissue pieces. The α1D-adrenergic agonist-stimulated response was increased in TSP-1-/- at 4 and 24 weeks but decreased at 12 weeks, and the ATP and MeSATP-stimulated peak [Ca2+]i responses were decreased at 24 weeks. These changes were observed prior to the appearance of mononuclear infiltrates. We conclude that in the lacrimal gland the absence of TSP-1: injures peripheral nerves; blocks efferent nerve activation; decreases protein secretion; and alters intracellular Ca2+ stores. Through these effects the absence of TSP-1 leads to disruption of ocular surface homeostasis and development of dry eye.
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Affiliation(s)
- Sumit Bhattacharya
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Laura García-Posadas
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Robin R Hodges
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Helen P Makarenkova
- Molecular Medicine Department, The Scripps Research Institute, La Jolla, CA, USA
| | - Sharmila Masli
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - Darlene A Dartt
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
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Rocha EM, Alves M, Rios JD, Dartt DA. The aging lacrimal gland: changes in structure and function. Ocul Surf 2015; 6:162-74. [PMID: 18827949 DOI: 10.1016/s1542-0124(12)70177-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The afferent nerves of the cornea and conjunctiva, efferent nerves of the lacrimal gland, and the lacrimal gland are a functional unit that works cooperatively to produce the aqueous component of tears. A decrease in the lacrimal gland secretory function can lead to dry eye disease. Because aging is a risk factor for dry eye disease, study of the changes in the function of the lacrimal gland functional unit with age is important for developing treatments to prevent dry eye disease. No one mechanism is known to induce the changes that occur with aging, although multiple different mechanisms have been associated with aging. These fall into two theoretical categories: programmed theories of aging (immunological, genetic, apoptotic, and neuroendocrine) and error theories of aging (protein alteration, somatic mutation, etc). Lacrimal glands undergo structural and functional alteration with increasing age. In mouse models of aging, it has been shown that neural stimulation of protein secretion is an early target of aging, accompanied by an increase in mast cells and lipofuscin accumulation. Hyperglycemia and increased lymphocytic infiltration can contribute to this loss of function at older ages. These findings suggest that an increase in oxidative stress may play a role in the loss of lacrimal gland function with age. For the afferent and efferent neural components of the lacrimal gland functional unit, immune or inflammatory mediated decrease in nerve function could contribute to loss of lacrimal gland secretion with age. More research in this area is critically needed.
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Affiliation(s)
- Eduardo M Rocha
- From the Department of Ophthalmology, Otorhinolaringology, and head and Neck Surgery, faculty of Medicine of Ribeirao Preto, Sao Paulo University Ribeirao, Preto, SP, Brazil; Laboratory of Clinical Physiopathology, Department of Clinical Medicine, faculty of Medical Sciences, State University of Campinas, Campinas, SP, Brazil; and Schepens Eye Research Institute and Department of Ophthalmology, harvard Medical School, Boston MA 02114 USA
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Kaja S, Hilgenberg JD, Rybalchenko V, Medina-Ortiz WE, Gregg EV, Koulen P. Polycystin-2 expression and function in adult mouse lacrimal acinar cells. Invest Ophthalmol Vis Sci 2011; 52:5605-11. [PMID: 21508103 DOI: 10.1167/iovs.10-7114] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Lacrimal glands regulate the production and secretion of tear fluid. Dysfunction of lacrimal gland acinar cells can ultimately result in ocular surface disorders, such as dry eye disease. Ca(2+) homeostasis is tightly regulated in the cellular environment, and secretion from the acinar cells of the lacrimal gland is regulated by both cholinergic and adrenergic stimuli, which both result in changes in the cytosolic Ca(2+) concentration. We have previously described the detailed intracellular distribution of inositol-1,4,5-trisphosphate receptors (IP(3)Rs), and ryanodine receptors (RyRs) in lacrimal acinar cells, however, little is known regarding the expression and distribution of the third major class of intracellular Ca(2+) release channels, transient receptor potential polycystin family (TRPP) channels. METHODS Studies were performed in adult lacrimal gland tissue of Swiss-Webster mice. Expression, localization, and intracellular distribution of TRPP Ca(2+) channels were investigated using immunocytochemistry, immunohistochemistry, and electron microscopy. The biophysical properties of single polycystin-2 channels were investigated using a planar lipid bilayer electrophysiology system. RESULTS All channel-forming isoforms of TRPP channels (polycystin-2, polycystin-L, and polycystin-2L2) were expressed in adult mouse lacrimal gland. Subcellular analysis of immunogold labeling revealed strongest polycystin-2 expression on the membranes of the endoplasmic reticulum, Golgi, and nucleus. Biophysical properties of lacrimal gland polycystin-2 channels were similar to those described for other tissues. CONCLUSIONS The expression of TRPP channels in lacrimal acinar cells suggests a functional role of the proteins in the regulation of lacrimal fluid secretion under physiological and disease conditions, and provides the basis for future studies focusing on physiology and pharmacology.
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Affiliation(s)
- Simon Kaja
- Vision Research Center, University of Missouri-Kansas City, School of Medicine, Kansas City, Missouri 64108, USA.
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Hodges RR, Vrouvlianis J, Scott R, Dartt DA. Identification of P2X₃ and P2X₇ purinergic receptors activated by ATP in rat lacrimal gland. Invest Ophthalmol Vis Sci 2011; 52:3254-63. [PMID: 21421865 DOI: 10.1167/iovs.10-7042] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE. To identify the type of purinergic receptors activated by adenosine triphosphate (ATP) in rat lacrimal gland and to determine their role in protein secretion. METHODS. Purinergic receptors were identified by RT-PCR, Western blot analysis, and immunofluorescence techniques. Acini from rat lacrimal gland were isolated by collagenase digestion. Acini were incubated with the fluorescence indicator fura-2 tetra-acetoxylmethyl ester, and intracellular [Ca(2+)] ([Ca(2+)](i)) was determined. Protein secretion was measured by fluorescence assay. RESULTS. The authors previously showed that P2X(7)receptors were functional in the lacrimal gland. In this study, they show that P2X(1-4) and P2X(6)receptors were identified in the lacrimal gland by RT-PCR, Western blot, and immunofluorescence analyses. P2X(5) receptors were not detected. ATP increased [Ca(2+)](i) and protein secretion in a concentration-dependent manner. Removal of extracellular Ca(2+) significantly reduced the ATP-stimulated increase in [Ca(2+)](i). Repeated applications of ATP caused desensitization of the [Ca(2+)](i) response. Incubation with the P2X(1) receptor inhibitor NF023 did not alter ATP-stimulated [Ca(2+)](i). Incubation with zinc, which potentiates P2X(2) and P2X(4) receptor responses, or lowering the pH to 6.8, which potentiates P2X(2) receptor responses, did not alter the ATP-stimulated [Ca(2+)](i). P2X(3) receptor inhibitors A-317491 and TNP-ATP significantly decreased ATP-stimulated [Ca(2+)](i) and protein secretion, whereas the P2X(3) receptor agonist α,β methylene ATP significantly increased them. The P2X(7) receptor inhibitor A438079 had no effect on ATP-stimulated [Ca(2+)](i) at 10(-6) M but did have an effect at 10(-4) M. CONCLUSIONS. Purinergic receptors P2X(1-4) and P2X(6) are present in the lacrimal gland. ATP uses P2X(3) and P2X(7) receptors to stimulate an increase in [Ca(2+)](i) and protein secretion.
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Affiliation(s)
- Robin R Hodges
- Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA.
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You S, Kublin CL, Avidan O, Miyasaki D, Zoukhri D. Isolation and propagation of mesenchymal stem cells from the lacrimal gland. Invest Ophthalmol Vis Sci 2011; 52:2087-94. [PMID: 21178145 DOI: 10.1167/iovs.10-5686] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Previously, it was reported that the murine lacrimal gland is capable of repair after experimentally induced injury and that the number of stem/progenitor cells was increased during the repair phase (2-3 days after injury). The aim of the present study was to determine whether these cells can be isolated from the lacrimal gland and propagated in vitro. METHODS Lacrimal gland injury was induced by injection of interleukin (IL)-1, and injection of saline vehicle served as control. Two and half days after injection, the lacrimal glands were removed and used to prepare explants or acinar cells for tissue culture. Cells derived from the explants and the acinar cells were grown in DMEM supplemented with 10% fetal bovine serum. Cells were stained for the stem cells markers, nestin, vimentin, ABCG2, and Sca-1. Cell proliferation was measured using an antibody against Ki67 or a cell-counting kit. The adipogenic capability of these cells was also tested in vitro. RESULTS Results show that nestin-positive cells can be isolated from IL-1-injected, but not saline-injected, lacrimal glands. A population of nestin-positive cells was also positive for vimentin, an intermediate filament protein expressed by mesenchymal cells. In addition, cultured cells expressed two other markers of stem cells, ABCG2 and Sca-1. These cells proliferated in vitro and can be induced to form adipocytes, attesting to their mesenchymal stem cell property. CONCLUSIONS Murine lacrimal glands contain mesenchymal stem cells that seem to play a pivotal role in tissue repair.
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Affiliation(s)
- Samantha You
- Department of General Dentistry, Tufts University School of Dental Medicine, Boston, Massachusetts 02111, USA
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Mechanisms involved in injury and repair of the murine lacrimal gland: role of programmed cell death and mesenchymal stem cells. Ocul Surf 2010; 8:60-9. [PMID: 20427009 DOI: 10.1016/s1542-0124(12)70070-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The non-keratinized epithelia of the ocular surface are constantly challenged by environmental insults, such as smoke, dust, and airborne pathogens. Tears are the sole physical protective barrier for the ocular surface. Production of tears in inadequate quantity or of inadequate quality results in constant irritation of the ocular surface, leading to dry eye disease, also referred to as keratoconjunctivitis sicca (KCS). Inflammation of the lacrimal gland, such as occurs in Sjogren syndrome, sarcoidosis, chronic graft-versus-host disease, and other pathological conditions, results in inadequate secretion of the aqueous layer of the tear film and is a leading cause of dry eye disease. The hallmarks of lacrimal gland inflammation are the presence of immune cell infiltrates, loss of acinar epithelial cells (the secreting cells), and increased production of proinflammatory cytokines. To date, the mechanisms leading to acinar cell loss and the associated decline in lacrimal gland secretion are still poorly understood. It is also not understood why the remaining lacrimal gland cells are unable to proliferate in order to regenerate a functioning lacrimal gland. This article reviews recent advances in exocrine tissue injury and repair, with emphasis on the roles of programmed cell death and stem/progenitor cells.
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Dartt DA. Neural regulation of lacrimal gland secretory processes: relevance in dry eye diseases. Prog Retin Eye Res 2009; 28:155-77. [PMID: 19376264 DOI: 10.1016/j.preteyeres.2009.04.003] [Citation(s) in RCA: 311] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The lacrimal gland is the major contributor to the aqueous layer of the tear film which consists of water, electrolytes and proteins. The amount and composition of this layer is critical for the health, maintenance, and protection of the cells of the cornea and conjunctiva (the ocular surface). Small changes in the concentration of tear electrolytes have been correlated with dry eye syndrome. While the mechanisms of secretion of water, electrolytes and proteins from the lacrimal gland differ, all three are under tight neural control. This allows for a rapid response to meet the needs of the cells of the ocular surface in response to environmental conditions. The neural response consists of the activation of the afferent sensory nerves in the cornea and conjunctiva to stimulate efferent parasympathetic and sympathetic nerves that innervate the lacrimal gland. Neurotransmitters are released from the stimulated parasympathetic and sympathetic nerves that cause secretion of water, electrolytes, and proteins from the lacrimal gland and onto the ocular surface. This review focuses on the neural regulation of lacrimal gland secretion under normal and dry eye conditions.
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Affiliation(s)
- Darlene A Dartt
- Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
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Dartt DA. Dysfunctional neural regulation of lacrimal gland secretion and its role in the pathogenesis of dry eye syndromes. Ocul Surf 2007; 2:76-91. [PMID: 17216081 DOI: 10.1016/s1542-0124(12)70146-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Tears are a complex fluid consisting of three layers, each of which is secreted by a different set of tissues or glands. The aqueous portion of the tear film is produced predominantly by the lacrimal gland. Dry eye syndromes are diseases in which the amount and composition of tears are altered, which can lead to ocular surface damage. There are many causes for dry eye syndromes. One such cause is the alteration in the functions of nerves innervating the lacrimal gland and the ocular surface. The autoimmune disease Sjogren syndrome can deleteriously affect the innervation of the lacrimal gland. Damage to the sensory nerves in the ocular surface, specifically the cornea, as a result of refractive surgery and normal aging, prevents the normal reflex arc to the lacrimal gland. Both defects can result in decreased tear secretion and dry eye syndromes. This review will discuss the current information regarding neurally-stimulated protein, water, and electrolyte secretion from the lacrimal gland and delineate how nerve dysfunction resulting from a variety of causes decreases secretion from this gland.
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Affiliation(s)
- Darlene A Dartt
- Schepens Eye Research Institute, and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA.
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Dawson LJ, Fox PC, Smith PM. Sjögrens syndrome—the non-apoptotic model of glandular hypofunction. Rheumatology (Oxford) 2006; 45:792-8. [PMID: 16595520 DOI: 10.1093/rheumatology/kel067] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- L J Dawson
- Oral Surgery, University of Liverpool Dental School, Room 1.10, Edwards Building, Daulby Street, Liverpool L69 3GN, UK.
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Zoukhri D. Effect of inflammation on lacrimal gland function. Exp Eye Res 2005; 82:885-98. [PMID: 16309672 PMCID: PMC1361268 DOI: 10.1016/j.exer.2005.10.018] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 10/06/2005] [Accepted: 10/17/2005] [Indexed: 12/21/2022]
Abstract
The lacrimal gland is the main contributor to the aqueous layer of the tear film. It secretes proteins, electrolytes and water, which helps to nourish and protect the ocular surface. Lacrimal gland secretion is primarily under neural control, which is achieved through a neural reflex arc. Stimuli to the ocular surface activate afferent sensory nerves in the cornea and conjunctiva. This in turn activates efferent parasympathetic and sympathetic nerves in the lacrimal gland to stimulate secretion. Sex steroid hormones are also important regulators of lacrimal gland functions. A decrease or lack of lacrimal gland secretion is the leading cause of aqueous tear deficient dry eye syndrome (DES). It has been suggested that DES is an inflammatory disorder that affects the ocular surface and the lacrimal gland. In several pathological instances, the lacrimal gland can become a target of the immune system and show signs of inflammation. This can result from autoimmune diseases (Sjögren's syndrome), organ transplantation (graft versus host disease), or simply as a result of aging. The hallmarks of lacrimal gland inflammation are the presence of focal lymphocytic infiltrates and increased production of proinflammatory cytokines. The mechanisms leading to lacrimal gland dysfunction are still poorly understood. Apoptosis, production of autoantibodies, hormonal imbalance, alterations in signaling molecules, neural dysfunction, and increased levels of proinflammatory cytokines have been proposed as possible mediators of lacrimal gland insufficiency in disease states.
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Affiliation(s)
- Driss Zoukhri
- Department of General Dentistry, Tufts University School of Dental Medicine, Boston, MA, USA.
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Dawson L, Tobin A, Smith P, Gordon T. Antimuscarinic antibodies in Sjögren's syndrome: Where are we, and where are we going? ACTA ACUST UNITED AC 2005; 52:2984-95. [PMID: 16200578 DOI: 10.1002/art.21347] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Luke Dawson
- University of Liverpool, Liverpool Merseyside, UK.
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Tensing EK, Törnwall J, Hukkanen M, Nordström DCE, Konttinen YT. The protein kinase C system in focal adenitis of the lacrimal gland in the non-obese diabetic mouse model for Sjögren's syndrome. ACTA ACUST UNITED AC 2004; 82:569-73. [PMID: 15453855 DOI: 10.1111/j.1600-0420.2004.00310.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Non-obese diabetic (NOD) mice develop an autoimmune exocrinopathy characterized by hyposecretion of saliva and acinar cell atrophy. As the protein kinase C (PKC) system is involved in the signal transduction pathways associated with primary secretion and acinar cell differentiation and growth, the PKC profile was analysed in NOD mice. METHODS Lacrimal glands from BALB/c, NOD, NOD scid and transgenic NOD x interferon-gamma (IFN-gamma) mice were analysed for their PKC profiles using antibodies against several conventional (alpha, beta, gamma), novel (delta, epsilon, theta) and atypical (iota, lambda) PKC isoforms using the Streptavidin/HRP (horseradish peroxidase) method. RESULTS Acinar cells in BALB/c control mice expressed two conventional (alpha, beta) and two atypical (iota, lambda) PKC isoforms. In NOD and transgenic NOD x IFN-gamma mice the same isoforms were more strongly expressed. NOD scid mice lacked all other PKC isoforms except PKC lambda. CONCLUSIONS Co-expression of several PKC isoforms in single cell type may be necessary for transcriptional activation and agonist-induced secretory responses. Hyposecretion in NOD mice was paradoxically associated with up-regulation of the PKC system. This may be associated with a deranged signal transduction per se rather than with the immune-inflammation, as the transgenic NOD x IFN-gamma mice showed similar PKC profiles. The NOD model does not reproduce lack/consumption of PKC II and PKC as in Sjögren's syndrome. This may be because the receptor autoantibodies in mice are directed against the adrenergic, not muscarinic, receptors. Lack and/or low level PKC expression in NOD scid mouse may explain the excessive acinar cell apoptosis in this model.
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Affiliation(s)
- E-K Tensing
- Department of Medicine/Invärtes Medicin, Helsinki University Central Hospital, Helsinki, Finland
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Qian L, Wang Y, Xie J, Rose CM, Yang T, Nakamura T, Sandberg M, Zeng H, Schechter JE, Chow RH, Hamm-Alvarez SF, Mircheff AK. Biochemical changes contributing to functional quiescence in lacrimal gland acinar cells after chronic ex vivo exposure to a muscarinic agonist. Scand J Immunol 2003; 58:550-65. [PMID: 14629627 DOI: 10.1046/j.1365-3083.2003.01343.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Profound secretory dysfunction can be associated with relatively modest lymphocytic infiltration of the lacrimal and salivary glands of Sjögren's syndrome (SjS) patients. SjS patients' sera contain autoantibodies to M3 muscarinic acetylcholine receptors (MAChR) that have variously been reported to have agonistic and antagonistic effects. We sought to identify consequences of chronic agonist stimulation by maintaining acinar cells from rabbit lacrimal glands for 20 h in the presence or absence of 10 microM carbachol (CCh). Exposure to CCh diminished the cells' ability to elevate cytosolic Ca2+ and secrete beta-hexosaminidase in response to acute stimulation with 100 microM CCh, but it enhanced their secretory responses to phenylephrine and ionomycin. Secretory vesicles appeared normal by electron microscopy, but confocal fluorescence microscopy revealed depletion of the secretory vesicle membrane marker, rab3D, and decreased ability to recruit secretory transport vesicles in response to acute 100 microM CCh. Additionally, the apical cortical actin cytoskeleton was disrupted and diminished compared to the basal-lateral cortical network. Subcellular fractionation analyses revealed that total membrane phase protein content was increased. The contents of beta-hexosaminidase and MAChR relative to total protein were not significantly altered, and MAChR abundance in the plasma membrane fraction was increased as the result of redistribution from endomembrane pools. However, relative cellular contents of the heterotrimeric guanosine triphosphate (GTP)-binding proteins, Gq and G11, were decreased. Additional biochemical changes included decreased contents of 47 kDa Gs and Gi3, protein kinase Calpha and rab3D and polymeric immunoglobulin (Ig) receptors; internalization of Na,K-ATPase from the plasma membranes to endomembrane compartments and decreased content of beta-hexosaminidase in the lysosomes. The observations demonstrate that chronic exposure to a MAChR agonist induces refractoriness to optimal stimulation, without causing receptor downregulation, by downregulating postreceptor-signalling mediators and effectors. The cells' secretory mechanisms for IgA and electrolytes also appear to be impaired, as does their ability to properly sort proteins to the lysosomes.
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Affiliation(s)
- L Qian
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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Kublin CL, Hodges RR, Zoukhri D. Proinflammatory cytokine inhibition of lacrimal gland secretion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 506:783-7. [PMID: 12613992 DOI: 10.1007/978-1-4615-0717-8_110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Affiliation(s)
- Claire Larkin Kublin
- Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
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18
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Zoukhri D, Kublin CL. Impaired neurotransmission in lacrimal and salivary glands of a murine model of Sjögren's syndrome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 506:1023-8. [PMID: 12614026 DOI: 10.1007/978-1-4615-0717-8_144] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Affiliation(s)
- Driss Zoukhri
- Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
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19
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Hodges RR, Dartt DA. Regulatory pathways in lacrimal gland epithelium. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 231:129-96. [PMID: 14713005 DOI: 10.1016/s0074-7696(03)31004-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tears are a complex fluid that continuously cover the exposed surface of the eye, namely the cornea and conjunctiva. Tears are secreted in response to the multitude of environmental stresses that can harm the ocular surface such as cold, mechanical stimulation, physical injury, noxious chemicals, as well as infections from various organisms. Tears also provide nutrients and remove waste from cells of the ocular surface. Because of the varied function of tears, tears are complex and are secreted by several different tissues. Tear secretion is under tight neural control allowing tears to respond rapidly to changing environmental conditions. The lacrimal gland is the main contributor to the aqueous portion of the tear film and the regulation of secretion from this gland has been well studied. Despite multiple redundencies in pathways to stimulate secretion from the lacrimal gland, defects can occur resulting in dry eye syndromes. These diseases can have deleterious effects on vision. In this review, we summarize the latest information regarding the regulatory pathways, which control secretion from the lacrimal gland, and their roles in the pathogenesis of dry eye syndromes.
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Affiliation(s)
- Robin R Hodges
- Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
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Beroukas D, Goodfellow R, Hiscock J, Jonsson R, Gordon TP, Waterman SA. Up-regulation of M3-muscarinic receptors in labial salivary gland acini in primary Sjögren's syndrome. J Transl Med 2002; 82:203-10. [PMID: 11850533 DOI: 10.1038/labinvest.3780412] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
M3-muscarinic receptors (M3R) mediate parasympathetic cholinergic neurotransmission to salivary and lacrimal glands, and autoantibodies to these receptors have been implicated in sicca symptoms and autonomic dysfunction in Sjögren's syndrome. We have investigated the expression of M3R in paraffin-embedded labial salivary glands (LSG) from seven patients with primary Sjögren's syndrome (pSS) and five healthy controls using high-resolution confocal microscopy and an affinity-purified goat polyclonal antibody raised against the COOH-terminal sequence of the human M3R. Immunolocalization of M3R was similar in control and pSS glands, with punctate staining of M3R in the basal membrane of acinar cells and in the luminal and abluminal membrane of myoepithelial cells. Bright, granular M3R staining was also detected in the cytoplasm and membranes of all intercalated and striated ducts, and infiltrating lymphocytes in pSS. All immunoreactivity was specifically blocked by the immunizing peptide. An increase in M3R expression specifically in acini in pSS was demonstrated by a 30% increase in receptor number per cluster and a 68% increase in the number of clusters in the membrane. This up-regulation is consistent with inhibition of parasympathetic neurotransmission, possibly by antagonistic autoantibodies to M3R. The up-regulation, rather than down-regulation, of M3R in acini of pSS LSG can explain the effectiveness of muscarinic agonists in treating sicca symptoms in pSS.
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Affiliation(s)
- Dimitra Beroukas
- Department of Immunology, Allergy and Arthritis, Flinders Medical Centre, Bedford Park, Australia
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21
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Abstract
Homeostasis of the tear film involves delicate hormonal and neuronal regulatory mechanisms. The eye appears to be a target organ for sex hormones, particularly the androgens, as they modulate the immune system and trophic functions of the lacrimal glands and the functioning of the meibomian glands. The cornea, lacrimal glands, mucous cells, and meibomian glands are all richly innervated, indicating the importance of nervous regulation in their function. Parasympathetic, sympathetic, and sensory innervation play complex stimulatory or inhibitory roles, and neuronal pathways interact via complex surface results cascades. Abnormalities at any point in these pathways can cause overall dysregulation of lacrimal function. Whatever the initial causes of dry eye, chronic dryness of the ocular surface results in inflammatory reactions and gradual destruction of the lacrimal glands and conjunctival epithelium. Once dry eye disease has developed, inflammation is the key mechanism of ocular surface injury, as both the cause and consequence of cell damage. In practice, dry eye can be associated with Sjögren's syndrome, allergies, infection, blepharitis, and preservative-containing eye drops.
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Affiliation(s)
- C Baudouin
- Service d'Ophtalmologie, CHNO Quinze-Vingts Paris and Hĵpital Ambroise-Paré, APHP, University of Paris V, Boulogne, France
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