1
|
Roshdy K, Massoud D, Al-Otaibi AM, Abumandour MMA. Histology, histochemistry and fine structure of the lacrimal gland in the one-humped camel (Camelus dromedarius). Anat Histol Embryol 2024; 53:e13051. [PMID: 38741549 DOI: 10.1111/ahe.13051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 04/27/2024] [Accepted: 05/02/2024] [Indexed: 05/16/2024]
Abstract
Our research aimed to provide complete histological, histochemical and ultrastructural features of the lacrimal gland of the one-humped camel (Camelus dromedarius) as well as novel insights into its adaptability to the Egyptian desert. Our study was applied to 20 fresh lacrimal glands collected from 10 camels instantly after their slaughtering. The results revealed that the gland was a compound tubulo-acinar gland, and its acini were enclosed by a thick connective tissue capsule that was very rich in elastic and collagen fibres. The gland acini had irregular lumens and were composed of conical to pyramidal cells. The nuclei of secretory cells were found in the basal part, and the cytoplasm was eosinophilic and granular. The glandular tissue consisted of serous and mucous acini and seromucous secretory cells. Histochemically, there was a significant amount of neutral mucopolysaccharides in the acini in which mucous cells had a significant periodic acid-Schiff (PAS)-positive reaction, whereas seromucous cells had a mild PAS-positive reaction. Ultrastructurally, the lacrimal cells had numerous secretory vesicles with contents of moderately to highly electron-dense cytoplasm. The nuclear envelope consisted of two prominent membranes surrounding the peri-nuclear cisterna. The acinar cells had numerous electron-lucent and moderately electron-dense secretory granules, mainly situated on the apical surface, and secreted their contents into the lumen. The luminal surface of the mucous secretory cells represents the remains of secretory granules discharged by the merocrine mechanism. In conclusion, the mucous secretion is believed to aid in the washing and moistening of the eyeball, particularly in dry, hot and dusty environments.
Collapse
Affiliation(s)
- Karam Roshdy
- Department of Histology and Cytology, Faculty of Veterinary Medicine, Alexandria University, Alexandria, Abees, Egypt
| | - Diaa Massoud
- Department of Biology, College of Science, Jouf University, Sakaka, Saudi Arabia
| | - Aljohara M Al-Otaibi
- Department of Biology, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Mohamed M A Abumandour
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Alexandria University, Alexandria, Abees, Egypt
| |
Collapse
|
2
|
Araujo ASL, Simões MDJ, Araujo-Jr OP, Simões RS, Baracat EC, Nader HB, Soares-Jr JM, Gomes RCT. Hyperprolactinemia modifies extracellular matrix components associated with collagen fibrillogenesis in harderian glands of non- and pregnant female mice. Exp Eye Res 2023; 235:109612. [PMID: 37580001 DOI: 10.1016/j.exer.2023.109612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 07/28/2023] [Accepted: 08/07/2023] [Indexed: 08/16/2023]
Abstract
The harderian gland (HG) is a gland located at the base of the nictating membrane and fills the inferomedial aspect of the orbit in rodents. It is under the influence of the hypothalamic-pituitary-gonadal axis and, because of its hormone receptors, it is a target tissue for prolactin (PRL) and sex steroid hormones (estrogen and progesterone). In humans and murine, the anterior surface of the eyes is protected by a tear film synthesized by glands associated with the eye. In order to understand the endocrine changes caused by hyperprolactinemia in the glands responsible for the formation of the tear film, we used an animal model with metoclopramide-induced hyperprolactinemia (HPRL). Given the evidences that HPRL can lead to a process of cell death and tissue fibrosis, the protein expression of small leucine-rich proteoglycans (SLRPs) was analyzed through immunohistochemistry in the HG of the non- and the pregnant female mice with hyperprolactinemia. The SRLPs are related to collagen fibrillogenesis and they participate in pro-apoptotic signals. Our data revealed that high prolactin levels and changes in steroid hormones (estrogen and progesterone) can lead to an alteration in the amount of collagen, and in the structure of type I and III collagen fibers through changes in the amounts of lumican and decorin, which are responsible for collagen fibrillogenesis. This fact can lead to the impaired functioning of the HG by excessive apoptosis in the HG of the non- and the pregnant female mice with HPRL and especially in the HG of pregnancy-associated hyperprolactinemia.
Collapse
Affiliation(s)
- Ariadne S L Araujo
- Morphology and Genetics Department, Federal University of São Paulo, UNIFESP, Brazil
| | - Manuel de J Simões
- Morphology and Genetics Department, Federal University of São Paulo, UNIFESP, Brazil; Faculty of Medicine University of São Paulo, Obstetrics and Gynecology Department, FMUSP, Brazil; Obstetrics and Gynecology Department, Federal University of São Paulo, UNIFESP, Brazil
| | - Osvaldo P Araujo-Jr
- Obstetrics and Gynecology Department, Federal University of São Paulo, UNIFESP, Brazil
| | - Ricardo S Simões
- Faculty of Medicine University of São Paulo, Obstetrics and Gynecology Department, FMUSP, Brazil; Obstetrics and Gynecology Department, Federal University of São Paulo, UNIFESP, Brazil
| | - Edmund C Baracat
- Faculty of Medicine University of São Paulo, Obstetrics and Gynecology Department, FMUSP, Brazil; Obstetrics and Gynecology Department, Federal University of São Paulo, UNIFESP, Brazil
| | - Helena B Nader
- Molecular Biology Division of the Department of Biochemistry, Federal University of São Paulo, Brazil
| | - José M Soares-Jr
- Faculty of Medicine University of São Paulo, Obstetrics and Gynecology Department, FMUSP, Brazil; Obstetrics and Gynecology Department, Federal University of São Paulo, UNIFESP, Brazil
| | - Regina C T Gomes
- Morphology and Genetics Department, Federal University of São Paulo, UNIFESP, Brazil; Faculty of Medicine University of São Paulo, Obstetrics and Gynecology Department, FMUSP, Brazil; Obstetrics and Gynecology Department, Federal University of São Paulo, UNIFESP, Brazil.
| |
Collapse
|
3
|
Araújo ASL, Verna C, Araújo Júnior OP, Soares Júnior JM, Simões RS, Baracat EC, Simões MDJ, Gomes RCT. Imbalance between the cellular proliferation and death in harderian gland of female mice with hyperprolactinemia. ACTA ACUST UNITED AC 2021; 67:650-655. [PMID: 34550251 DOI: 10.1590/1806-9282.20200737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 09/20/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To assess the impact of the metoclopramide-induced hyperprolactinemia in cellular death and proliferation in the harderian gland of female mice. METHODS Twenty female mice were divided into two groups of 10 animals each and treated: 0.2 mL of saline solution (controls, Ctr) and 200 µg of metoclopramide (experimental, hyperprolactinemia), both for 50 consecutive days and at 12:00 a.m. On the 50th day, the female were euthanized, and the harderian glands were removed and processed for immunohistochemistry for detected ki67 and TUNEL method. Data were statistically analyzed by unpaired Student's t test (p<0.05). RESULTS The harderian gland of the hyperprolactinemia group showed increase in the immunoexpression of Ki67 and TUNEL compared to the Ctr group (p<0.05), and there was no significant difference in the amount of porphyrin in the HPrl group compared to the Ctr group. CONCLUSION The hyperprolactinemia led to increased cell death in the acini the harderian gland and cell proliferation in the stroma glandular, fact that suggesting a reduction process of cellular activity and fibrosis, which suggests impairment in the functioning of the lacrimal harderian.
Collapse
Affiliation(s)
| | - Carina Verna
- Universidade Federal de São Paulo, Morphology and Genetics Department - São Paulo (SP), Brazil
| | | | - José Maria Soares Júnior
- Universidade de São Paulo, Faculty of Medicine Obstetrics and Gynecology Department - São Paulo (SP), Brazil
| | - Ricardo Santos Simões
- Universidade de São Paulo, Faculty of Medicine Obstetrics and Gynecology Department - São Paulo (SP), Brazil
| | - Edmund Chada Baracat
- Universidade de São Paulo, Faculty of Medicine Obstetrics and Gynecology Department - São Paulo (SP), Brazil
| | - Manuel de Jesus Simões
- Universidade Federal de São Paulo, Morphology and Genetics Department - São Paulo (SP), Brazil
| | - Regina Célia Teixeira Gomes
- Universidade Federal de São Paulo, Morphology and Genetics Department - São Paulo (SP), Brazil.,Universidade de São Paulo, Faculty of Medicine Obstetrics and Gynecology Department - São Paulo (SP), Brazil
| |
Collapse
|
4
|
Dolai S, Liang T, Orabi AI, Holmyard D, Xie L, Greitzer-Antes D, Kang Y, Xie H, Javed TA, Lam PP, Rubin DC, Thorn P, Gaisano HY. Pancreatitis-Induced Depletion of Syntaxin 2 Promotes Autophagy and Increases Basolateral Exocytosis. Gastroenterology 2018; 154:1805-1821.e5. [PMID: 29360461 PMCID: PMC6461447 DOI: 10.1053/j.gastro.2018.01.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 12/13/2017] [Accepted: 01/08/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Pancreatic acinar cells are polarized epithelial cells that store enzymes required for digestion as inactive zymogens, tightly packed at the cell apex. Stimulation of acinar cells causes the zymogen granules to fuse with the apical membrane, and the cells undergo exocytosis to release proteases into the intestinal lumen. Autophagy maintains homeostasis of pancreatic acini. Syntaxin 2 (STX2), an abundant soluble N-ethyl maleimide sensitive factor attachment protein receptor in pancreatic acini, has been reported to mediate apical exocytosis. Using human pancreatic tissues and STX2-knockout (KO) mice, we investigated the functions of STX2 in zymogen granule-mediated exocytosis and autophagy. METHODS We obtained pancreatic tissues from 5 patients undergoing surgery for pancreatic cancer and prepared 80-μm slices; tissues were exposed to supramaximal cholecystokinin octapeptide (CCK-8) or ethanol and a low concentration of CCK-8 and analyzed by immunoblot and immunofluorescence analyses. STX2-KO mice and syntaxin 2+/+ C57BL6 mice (controls) were given intraperitoneal injections of supramaximal caerulein (a CCK-8 analogue) or fed ethanol and then given a low dose of caerulein to induce acute pancreatitis, or saline (controls); pancreata were isolated and analyzed by histology and immunohistochemistry. Acini were isolated from mice, incubated with CCK-8, and analyzed by immunofluorescence microscopy or used in immunoprecipitation experiments. Exocytosis was quantified using live-cell exocytosis and Ca2+ imaging analyses and based on formation of exocytotic soluble N-ethyl maleimide sensitive factor attachment protein receptor complexes. Dysregulations in autophagy were identified using markers, electron and immunofluorescence microscopy, and protease activation assays. RESULTS Human pancreatic tissues and dispersed pancreatic acini from control mice exposed to CCK-8 or ethanol plus CCK-8 were depleted of STX2. STX2-KO developed more severe pancreatitis after administration of supramaximal caerulein or a 6-week ethanol diet compared with control. Acini from STX2-KO mice had increased apical exocytosis after exposure to CCK-8, as well as increased basolateral exocytosis, which led to ectopic release of proteases. These increases in apical and basolateral exocytosis required increased formation of fusogenic soluble N-ethyl maleimide sensitive factor attachment protein receptor complexes, mediated by STX3 and STX4. STX2 bound ATG16L1 and prevented it from binding clathrin. Deletion of STX2 from acini increased binding of AT16L1 to clathrin, increasing formation of pre-autophagosomes and inducing autophagy. Induction of autophagy promoted the CCK-8-induced increase in autolysosome formation and the activation of trypsinogen. CONCLUSIONS In studies of human pancreatic tissues and pancreata from STX2-KO and control mice, we found STX2 to block STX3- and STX4-mediated fusion of zymogen granules with the plasma membrane and exocytosis and prevent binding of ATG16L1 to clathrin, which contributes to induction of autophagy. Exposure of pancreatic tissues to CCK-8 or ethanol depletes acinar cells of STX2, increasing basolateral exocytosis and promoting autophagy induction, leading to activation of trypsinogen.
Collapse
Affiliation(s)
- Subhankar Dolai
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
| | - Tao Liang
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Abrahim I. Orabi
- Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Douglas Holmyard
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Li Xie
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | | | - Youhou Kang
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Huanli Xie
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Tanveer A. Javed
- Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Patrick P. Lam
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Deborah C. Rubin
- Division of Gastroenterology, Departments of Medicine, and Developmental Biology, Washington University School of Medicine, St Louis Missouri
| | - Peter Thorn
- University of Sydney, Sydney, New South Wales, Australia
| | - Herbert Y. Gaisano
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada,Department of Physiology, University of Toronto Toronto, Ontario, Canada
| |
Collapse
|
5
|
Dolai S, Liang T, Orabi AI, Xie L, Holmyard D, Javed TA, Fernandez NA, Xie H, Cattral MS, Thurmond DC, Thorn P, Gaisano HY. Depletion of the membrane-fusion regulator Munc18c attenuates caerulein hyperstimulation-induced pancreatitis. J Biol Chem 2017; 293:2510-2522. [PMID: 29284677 DOI: 10.1074/jbc.ra117.000792] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/21/2017] [Indexed: 12/26/2022] Open
Abstract
Epithelial pancreatic acinar cells perform crucial functions in food digestion, and acinar cell homeostasis required for secretion of digestive enzymes relies on SNARE-mediated exocytosis. The ubiquitously expressed Sec1/Munc18 protein mammalian uncoordinated-18c (Munc18c) regulates membrane fusion by activating syntaxin-4 (STX-4) to bind cognate SNARE proteins to form a SNARE complex that mediates exocytosis in many cell types. However, in the acinar cell, Munc18c's functions in exocytosis and homeostasis remain inconclusive. Here, we found that pancreatic acini from Munc18c-depleted mice (Munc18c+/-) and human pancreas (lenti-Munc18c-shRNA-treated) exhibit normal apical exocytosis of zymogen granules (ZGs) in response to physiologic stimulation with the intestinal hormone cholecystokinin (CCK-8). However, when stimulated with supraphysiologic CCK-8 levels to mimic pancreatitis, Munc18c-depleted (Munc18c+/-) mouse acini exhibited a reduction in pathological basolateral exocytosis of ZGs resulting from a decrease in fusogenic STX-4 SNARE complexes. This reduced basolateral exocytosis in part explained the less severe pancreatitis observed in Munc18c+/- mice after hyperstimulation with the CCK-8 analog caerulein. Likely as a result of this secretory blockade, Munc18c-depleted acini unexpectedly activated a component of the endoplasmic reticulum (ER) stress response that contributed to autophagy induction, resulting in downstream accumulation of autophagic vacuoles and autolysosomes. We conclude that Munc18c's role in mediating ectopic basolateral membrane fusion of ZGs contributes to the initiation of CCK-induced pancreatic injury, and that blockade of this secretory process could increase autophagy induction.
Collapse
Affiliation(s)
- Subhankar Dolai
- From the Departments of Medicine and .,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Tao Liang
- From the Departments of Medicine and.,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Abrahim I Orabi
- Division of Pediatric Gastroenterology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Li Xie
- From the Departments of Medicine and.,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Douglas Holmyard
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Tanveer A Javed
- Division of Pediatric Gastroenterology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | | | | | - Mark S Cattral
- Toronto General Hospital Research Institute, University Health Network, University of Toronto, Toronto, Ontario M5G 2N2, Canada
| | - Debbie C Thurmond
- Beckman Research Institute of the City of Hope, Duarte, California 91010, and
| | - Peter Thorn
- School of Biomedical Sciences,University of Sydney, Sydney, New South Wales 2050, Australia
| | - Herbert Y Gaisano
- From the Departments of Medicine and .,Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| |
Collapse
|
6
|
Jakobiec FA, Syed ZA, Stagner AM, Harris GJ, Rootman J, Yoon MK, Mombaerts I. Orbital Inflammation in Pregnant Women. Am J Ophthalmol 2016; 166:91-102. [PMID: 27038895 DOI: 10.1016/j.ajo.2016.03.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/18/2016] [Accepted: 03/23/2016] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To analyze overlaps between pregnancy and orbital inflammation (OI). DESIGN Retrospective observational case series. METHODS Eight new cases from 1997 to 2015 and 2 previously published cases were identified for inclusion in this investigation to provide the fullest clinical picture. Medical records, imaging studies, and the results of biopsies were reviewed. RESULTS Three categories of association were discovered: (1) OI arising for the first time during pregnancy (5 cases); (2) OI arising within 3 months of delivery (2 cases); and (3) previously diagnosed OI reactivated or exacerbated by pregnancy (3 cases). One patient had a preexistent systemic autoimmune disease and another's was later diagnosed. One patient had attacks during sequential pregnancies. Findings included eyelid swelling and erythema, conjunctival chemosis, pain on eye movement, minimal diplopia, the usual absence of proptosis, and general preservation of visual acuity. Imaging studies disclosed extraocular muscle swelling (8 cases), most frequently of a single lateral rectus muscle. There were 2 cases of dacryoadenitis; 1 of these and an additional case displayed inflammation of the retrobulbar fat. Corticosteroids effected resolution of most symptoms. Singleton births were normal with the exceptions of an intrauterine fetal demise owing to acrania and a molar pregnancy. CONCLUSION OI usually affects a single rectus muscle (typically the lateral) and, less often, the lacrimal gland and is often mild when it arises during or after pregnancy. Independent systemic autoimmune disease is an uncommon feature. Corticosteroids were efficacious except in 1 case with severe orbital scarring. No definitive causal relationships between pregnancy and OI could be established based on the clinical data.
Collapse
Affiliation(s)
- Frederick A Jakobiec
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts; David G. Cogan Laboratory of Ophthalmic Pathology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
| | - Zeba A Syed
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts
| | - Anna M Stagner
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts; David G. Cogan Laboratory of Ophthalmic Pathology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Gerald J Harris
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Jack Rootman
- Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, Canada
| | - Michael K Yoon
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts
| | - Ilse Mombaerts
- Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium
| |
Collapse
|
7
|
Araujo ASL, de Jesus Simões M, Verna C, Simões RS, Júnior JMS, Baracat EC, Gomes RCT. Influence of hyperprolactinemia on collagen fibers in the lacrimal gland of female mice. Clinics (Sao Paulo) 2015; 70:632-7. [PMID: 26375566 PMCID: PMC4557571 DOI: 10.6061/clinics/2015(09)07] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE To quantify the collagen fibers in the lacrimal gland of female mice with hyperprolactinemia. METHODS Forty adult female mice were randomly divided into two groups with 20 animals each: nonpregnant control (CTR1, control group, 0.2 mL of saline solution) and nonpregnant experimental (HPRL1, experimental group, 200 µg/day metoclopramide). Treatments lasted for 50 consecutive days. On day 50, 10 females from each group (control and experimental) were euthanized in the proestrus phase; then, the blood was collected and the lacrimal glands were removed. Thereafter, the remaining females were placed with the mates and continued to receive treatment with saline solution or metoclopramide. On the 6th post-coital day, 10 pregnant females from the control group (CTR2) and 10 pregnant females from the experimental group (HPRL2) were euthanized, after which blood was collected and the lacrimal glands removed. The lacrimal glands were processed for morphological analyses and collagen quantification, and prolactin and sex steroid levels were measured in the blood samples. Data were statistically analyzed using an unpaired Student t test (p<0.05). RESULTS Morphological analysis revealed greater structural tissue disorganization of the lacrimal glands in the metoclopramide-treated groups. The total collagen content was significantly higher in the HPRL1 group than in the CTR1 group (p<0.05), whereas the difference between the CTR2 and HPRL2 groups was not significant. CONCLUSION Our data suggest an impairment in the functioning of the lacrimal gland as a consequence of increased prolactin levels and decreased serum levels of estrogen and progesterone.
Collapse
Affiliation(s)
- Ariadne Stavare Leal Araujo
- Universidade Federal de São Paulo (UNIFESP), Morfologia e Genética
- Universidade Federal de São Paulo (UNIFESP), Oftalmologia, São Paulo/, SP, Brazil
| | - Manuel de Jesus Simões
- Universidade Federal de São Paulo (UNIFESP), Ginecologia, São Paulo/, SP, Brazil
- Universidade Federal de São Paulo (UNIFESP), Morfologia e Genética
| | - Carina Verna
- Universidade Federal de São Paulo (UNIFESP), Ginecologia, São Paulo/, SP, Brazil
- Universidade Federal de São Paulo (UNIFESP), Oftalmologia, São Paulo/, SP, Brazil
| | | | - José Maria Soares Júnior
- Faculdade de Medicina da Universidade de São Paulo, Obstetricia e Ginecologia, São Paulo/, SP, Brazil
| | - Edmund Chada Baracat
- Faculdade de Medicina da Universidade de São Paulo, Obstetricia e Ginecologia, São Paulo/, SP, Brazil
| | - Regina Célia Teixeira Gomes
- Universidade Federal de São Paulo (UNIFESP), Ginecologia, São Paulo/, SP, Brazil
- Universidade Federal de São Paulo (UNIFESP), Morfologia e Genética
- Faculdade de Medicina da Universidade de São Paulo, Obstetricia e Ginecologia, São Paulo/, SP, Brazil
- Corresponding author: E-mail:
| |
Collapse
|
8
|
Harvey S, Martínez-Moreno CG, Luna M, Arámburo C. Autocrine/paracrine roles of extrapituitary growth hormone and prolactin in health and disease: An overview. Gen Comp Endocrinol 2015; 220:103-11. [PMID: 25448258 DOI: 10.1016/j.ygcen.2014.11.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/03/2014] [Indexed: 02/07/2023]
Abstract
Growth hormone (GH) and prolactin (PRL) are both endocrines that are synthesized and released from the pituitary gland into systemic circulation. Both are therefore hormones and both have numerous physiological roles mediated through a myriad of target sites and both have pathophysiological consequences when present in excess or deficiency. GH or PRL gene expression is not, however, confined to the anterior pituitary gland and it occurs widely in many of their central and peripheral sites of action. This may reflect "leaky gene" phenomena and the fact that all cells have the potential to express every gene that is present in their genome. However, the presence of GH or PRL receptors in these extrapituitary sites of GH and PRL production suggests that they are autocrine or paracrine sites of GH and PRL action. These local actions often occur prior to the ontogeny of pituitary somatotrophs and lactotrophs and they may complement or differ from the roles of their pituitary counterparts. Many of these local actions are also of physiological significance, since they are impaired by a blockade of local GH or PRL production or by an antagonism of local GH or PRL action. These local actions may also be of pathophysiological significance, since autocrine or paracrine actions of GH and PRL are thought to be causally involved in a number of disease states, particularly in cancer. Autocrine GH for instance, is thought to be more oncogenic than pituitary GH and selective targeting of the autocrine moiety may provide a therapeutic approach to prevent tumor progression. In summary, GH and PRL are not just endocrine hormones, as they have autocrine and/or paracrine roles in health and disease.
Collapse
Affiliation(s)
- Steve Harvey
- Department of Physiology, University of Alberta, Edmonton T6G 2H7, Canada.
| | | | - Maricela Luna
- Departamento de Neurobiología, Celular y Molecular Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Qro. 76230, Mexico
| | - Carlos Arámburo
- Departamento de Neurobiología, Celular y Molecular Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Qro. 76230, Mexico
| |
Collapse
|
9
|
Petridou B. Differences in affinities between the homologous and the heterologous rabbit prolactin-receptor interaction with respect to proliferation and differentiation activities. Gen Comp Endocrinol 2015; 213:118-29. [PMID: 25449135 DOI: 10.1016/j.ygcen.2014.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 09/08/2014] [Accepted: 10/23/2014] [Indexed: 11/23/2022]
Abstract
Interspecies differences in PRL-receptor binding and their relationship with bioactivity deserve investigation since cross-reactivity is relevant to the design of many experiments. We have previously shown that the lower affinity of rabbit prolactin (rbPRL) binding to its homologous receptor is due to its faster and more complete dissociation compared with that of ovine PRL (oPRL). In order to obtain sufficient amounts of rbPRL to study the functional consequences of its low affinity homologous interaction, rbPRL was expressed recombinantly in Escherichia coli (rec rbPRL) as insoluble inclusion bodies, refolded and purified to homogeneity, yielding electrophoretically pure, over 98% monomeric rec rbPRL. Proper renaturation of rec rbPRL was evidenced by comparison of its CD spectra, binding parameters and bioactivity with those determined for the rbPRL. The binding potency of rec rbPRL to its receptor, expressed either endogenously in the mammary gland or recombinantly in mammalian cells is one log unit lower than that to the receptor expressed recombinantly in insect cells. This difference is probably related to differences in cell-dependent receptor densities. The proliferation potency of rbPRL or rec rbPRL was one log unit lower than that of oPRL, consistent with its lower binding affinity, but the differentiation potencies of these PRLs were similar. Thus, the proliferation activity is sensitive to PRL-receptor affinity and dissociation kinetics, whereas the differentiation response is marginally modulated.
Collapse
Affiliation(s)
- Barbara Petridou
- UMR 1313 Génétique Animale et Biologie Intégrative, INRA Institut National de la Recherche Agronomique, F-78352 Jouy-en-Josas, France
| |
Collapse
|
10
|
Mircheff AK, Wang Y, Ding C, Warren DW, Schechter JE. Potentially pathogenic immune cells and networks in apparently healthy lacrimal glands. Ocul Surf 2015; 13:47-81. [PMID: 25557346 DOI: 10.1016/j.jtos.2014.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/05/2014] [Accepted: 06/05/2014] [Indexed: 12/22/2022]
Abstract
Lacrimal glands of people over 40 years old frequently contain lymphocytic infiltrates. Relationships between histopathological presentation and physiological dysfunction are not straightforward. Data from rabbit studies have suggested that at least two immune cell networks form in healthy lacrimal glands, one responding to environmental dryness, the other to high temperatures. New findings indicate that mRNAs for several chemokines and cytokines are expressed primarily in epithelial cells; certain others are expressed in both epithelial cells and immune cells. Transcript abundances vary substantially across glands from animals that have experienced the same conditions, allowing for correlation analyses, which detect clusters that map to various cell types and to networks of coordinately functioning cells. A core network--expressing mRNAs including IL-1α, IL-6, IL-17A, and IL-10--expands adaptively with exposure to dryness, suppressing IFN-γ, but potentially causing physiological dysfunction. High temperature elicits concurrent increases of mRNAs for prolactin (PRL), CCL21, and IL-18. PRL is associated with crosstalk to IFN-γ, BAFF, and IL-4. The core network reacts to the resulting PRL-BAFF-IL-4 network, creating a profile reminiscent of Sjögren's disease. In a warmer, moderately dry setting, PRL-associated increases of IFN-γ are associated with suppression of IL-10 and augmentations of IL-1α and IL-17, creating a profile reminiscent of severe chronic inflammation.
Collapse
Affiliation(s)
- Austin K Mircheff
- Department of Physiology & Biophysics, Keck School of Medicine and School of Pharmacy, University of Southern California, Los Angeles, California; Department of Ophthalmology, Doheny Eye Institute, Keck School of Medicine and School of Pharmacy, University of Southern California, Los Angeles, California.
| | - Yanru Wang
- Department of Physiology & Biophysics, Keck School of Medicine and School of Pharmacy, University of Southern California, Los Angeles, California
| | - Chuanqing Ding
- Department of Pharmacology & Pharmaceutical Sciences, Keck School of Medicine and School of Pharmacy, University of Southern California, Los Angeles, California; Department of Cell & Neurobiology, Keck School of Medicine and School of Pharmacy, University of Southern California, Los Angeles, California
| | - Dwight W Warren
- Department of Cell & Neurobiology, Keck School of Medicine and School of Pharmacy, University of Southern California, Los Angeles, California
| | - Joel E Schechter
- Department of Cell & Neurobiology, Keck School of Medicine and School of Pharmacy, University of Southern California, Los Angeles, California
| |
Collapse
|
11
|
Selvam S, Mircheff AK, Yiu SC. Diverse mediators modulate the chloride ion fluxes that drive lacrimal fluid production. Invest Ophthalmol Vis Sci 2013; 54:2927-33. [PMID: 23513060 DOI: 10.1167/iovs.12-10202] [Citation(s) in RCA: 7] [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 To learn whether locally expressed and systemic mediators might modulate the cholinergically induced transepithelial Cl(-) fluxes that underlie lacrimal fluid production. METHODS Reconstituted epithelial monolayers were exposed to a submaximal dose of the muscarinic agonist, carbachol (CCh), or to one of several paracrine mediators for 18 hours, then acutely stimulated with an optimal dose of CCh. Secretory Cl(-) fluxes were assessed as negative short-circuit currents (ISC). RESULTS Exposure to IL-6 at concentrations of 1 and 10 ng/mL and IL-1β at 10 ng/mL significantly decreased CCh-induced Cl(-) secretion. Prolactin decreased CCh-induced Cl(-) secretion, but the extent of the decrease diminished as the prolactin concentration increased from 20 to 200 ng/mL. CCh, 10 μM, prevented CCh, 100 μM, from eliciting Cl(-) secretion. Exposure to histamine, 10 mM, prevented formation of confluent monolayers. Exposure to histamine, 1 mM, decreased CCh-induced Cl(-) secretion, whereas exposure to 5-HT, 1 mM, potentiated CCh-induced Cl(-) secretion. CONCLUSIONS Chronic exposure to inflammatory cytokines may significantly impair cholinergically induced lacrimal fluid production. Concentrations of prolactin within the high range of normal values also may impair fluid production, but this effect is reversed at levels associated with pregnancy. Autonomic neurotransmitters and paracrine mediators that signal through different G protein-coupled receptors appear to exert varying influences, which range from complete suppression to potentiation of cholinergically induced fluid production. Thus, some hormones and paracrine mediators may impair secretion in apparently homeostatic glands as well as diseased glands, whereas mediators produced by certain immune cell infiltrates may actually enhance fluid formation.
Collapse
Affiliation(s)
- Shivaram Selvam
- Department of Ophthalmology, Doheny Eye Institute, and Department of Physiology and Biophysics, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | | | | |
Collapse
|
12
|
Ubels JL, Gipson IK, Spurr-Michaud SJ, Tisdale AS, Van Dyken RE, Hatton MP. Gene expression in human accessory lacrimal glands of Wolfring. Invest Ophthalmol Vis Sci 2012; 53:6738-47. [PMID: 22956620 DOI: 10.1167/iovs.12-10750] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE The accessory lacrimal glands are assumed to contribute to the production of tear fluid, but little is known about their function. The goal of this study was to conduct an analysis of gene expression by glands of Wolfring that would provide a more complete picture of the function of these glands. METHODS Glands of Wolfring were isolated from frozen sections of human eyelids by laser microdissection. RNA was extracted from the cells and hybridized to gene expression arrays. The expression of several of the major genes was confirmed by immunohistochemistry. RESULTS Of the 24 most highly expressed genes, 9 were of direct relevance to lacrimal function. These included lysozyme, lactoferrin, tear lipocalin, and lacritin. The glands of Wolfring are enriched in genes related to protein synthesis, targeting, and secretion, and a large number of genes for proteins with antimicrobial activity were detected. Ion channels and transporters, carbonic anhydrase, and aquaporins were abundantly expressed. Genes for control of lacrimal function, including cholinergic, adrenergic, vasoactive intestinal polypeptide, purinergic, androgen, and prolactin receptors were also expressed in gland of Wolfring. CONCLUSIONS The data suggest that the function of glands of Wolfring is similar to that of main lacrimal glands and are consistent with secretion electrolytes, fluid, and protein under nervous and hormonal control. Since these glands secrete directly onto the ocular surface, their location may allow rapid response to exogenous stimuli and makes them readily accessible to topical drugs.
Collapse
Affiliation(s)
- John L Ubels
- Department of Biology, Calvin College, Grand Rapids, Michigan 49546, USA.
| | | | | | | | | | | |
Collapse
|
13
|
Chiang L, Ngo J, Schechter JE, Karvar S, Tolmachova T, Seabra MC, Hume AN, Hamm-Alvarez SF. Rab27b regulates exocytosis of secretory vesicles in acinar epithelial cells from the lacrimal gland. Am J Physiol Cell Physiol 2011; 301:C507-21. [PMID: 21525430 DOI: 10.1152/ajpcell.00355.2010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tear proteins are supplied by the regulated fusion of secretory vesicles at the apical surface of lacrimal gland acinar cells, utilizing trafficking mechanisms largely yet uncharacterized. We investigated the role of Rab27b in the terminal release of these secretory vesicles. Confocal fluorescence microscopy analysis of primary cultured rabbit lacrimal gland acinar cells revealed that Rab27b was enriched on the membrane of large subapical vesicles that were significantly colocalized with Rab3D and Myosin 5C. Stimulation of cultured acinar cells with the secretagogue carbachol resulted in apical fusion of these secretory vesicles with the plasma membrane. Evaluation of morphological changes by transmission electron microscopy of lacrimal glands from Rab27b(-/-) and Rab27(ash/ash)/Rab27b(-/-) mice, but not ashen mice deficient in Rab27a, showed changes in abundance and organization of secretory vesicles, further confirming a role for this protein in secretory vesicle exocytosis. Glands lacking Rab27b also showed increased lysosomes, damaged mitochondria, and autophagosome-like organelles. In vitro, expression of constitutively active Rab27b increased the average size but retained the subapical distribution of Rab27b-enriched secretory vesicles, whereas dominant-negative Rab27b redistributed this protein from membrane to the cytoplasm. Functional studies measuring release of a cotransduced secretory protein, syncollin-GFP, showed that constitutively active Rab27b enhanced, whereas dominant-negative Rab27b suppressed, stimulated release. Disruption of actin filaments inhibited vesicle fusion to the apical membrane but did not disrupt homotypic fusion. These data show that Rab27b participates in aspects of lacrimal gland acinar cell secretory vesicle formation and release.
Collapse
Affiliation(s)
- Lilian Chiang
- School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Mircheff AK, Wang Y, Thomas PB, Nakamura T, Samant D, Trousdale MD, Warren DW, Ding C, Schechter JE. Systematic Variations in Immune Response-Related Gene Transcript Abundance Suggest New Questions about Environmental Influences on Lacrimal Gland Immunoregulation. Curr Eye Res 2011; 36:285-94. [DOI: 10.3109/02713683.2010.550408] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
15
|
Fernandez NA, Liang T, Gaisano HY. Live pancreatic acinar imaging of exocytosis using syncollin-pHluorin. Am J Physiol Cell Physiol 2011; 300:C1513-23. [PMID: 21307342 DOI: 10.1152/ajpcell.00433.2010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this report, a novel live acinar exocytosis imaging technique is described. An adenovirus was engineered, encoding for an endogenous zymogen granule (ZG) protein (syncollin) fused to pHluorin, a pH-dependent green fluorescent protein (GFP). Short-term culture of mouse acini infected with this virus permits exogenous adenoviral protein expression while retaining acinar secretory competence and cell polarity. The syncollin-pHluorin fusion protein was shown to be correctly localized to ZGs, and the pH-dependent fluorescence of pHluorin was retained. Coupled with the use of a spinning disk confocal microscope, the syncollin-pHluorin fusion protein exploits the ZG luminal pH changes that occur during exocytosis to visualize exocytic events of live acinar cells in real-time with high spatial resolution in three dimensions. Apical and basolateral exocytic events were observed on stimulation of acinar cells with maximal and supramaximal cholecystokinin concentrations, respectively. Sequential exocytic events were also observed. Coupled with the use of transgenic mice and/or adenovirus-mediated protein expression, this syncollin-pHluorin imaging method offers a superior approach to studying pancreatic acinar exocytosis. This assay can also be applied to acinar disease models to elucidate the mechanisms implicated in pancreatitis.
Collapse
Affiliation(s)
- Nestor A Fernandez
- Dept. of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada
| | | | | |
Collapse
|
16
|
Lkhider M, Seddiki T, Ollivier-Bousquet M. La prolactine et son fragment 16 kDa dans les tissus de mammifères. Med Sci (Paris) 2010; 26:1049-55. [DOI: 10.1051/medsci/201026121049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
17
|
Schechter JE, Warren DW, Mircheff AK. A Lacrimal Gland is a Lacrimal Gland, But Rodent's and Rabbit's Are Not Human. Ocul Surf 2010; 8:111-34. [DOI: 10.1016/s1542-0124(12)70222-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
18
|
Zinc transporter-2 (ZnT2) variants are localized to distinct subcellular compartments and functionally transport zinc. Biochem J 2009; 422:43-52. [PMID: 19496757 DOI: 10.1042/bj20081189] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ZnT2 (zinc transporter-2) expression is restricted to tissues with unique zinc requirements such as mammary and prostate glands. We previously determined that ZnT2 plays a major role in zinc export from mammary glands, as women with a mutation in the gene encoding ZnT2 (SLC30A2) had an approximately 75% reduction in milk zinc concentration. Two distinct human ZnT2 isoforms (approximately 42 and 35 kDa) are predicted to result from alternative splicing of SLC30A2. We examined the localization and function of each ZnT2 isoform, in cells generated to express ZnT2-HA (haemagglutinin) fusion proteins. The 42 kDa isoform was localized primarily to the endosomal/secretory compartment and overexpression resulted in increased zinc vesicularization. In contrast, the 35 kDa isoform is associated with the plasma membrane. Importantly, zinc transport was higher in cells over-expressing each isoform, indicating that both proteins are functional. Endogenous expression of the secretory vesicle-associated ZnT2 isoform predominates in mammary cells and expression is higher in secreting cells, whereas the smaller isoform plays a minor role in zinc export, directly reflecting the secretory function of the mammary gland. Together our data shed further light on the complex integration of cellular zinc transport mechanisms, which may be facilitated by multiple isoforms of specific zinc transporters with unique cellular functions.
Collapse
|
19
|
de Saint Jean M, Nakamura T, Wang Y, Trousdale MD, Schechter JE, Mircheff AK. Suppression of lymphocyte proliferation and regulation of dendritic cell phenotype by soluble mediators from rat lacrimal epithelial cells. Scand J Immunol 2009; 70:53-62. [PMID: 19522768 DOI: 10.1111/j.1365-3083.2009.02272.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lacrimal epithelial cells appear to constitutively secrete autoantigens to their underling stroma. The present experiments address the hypothesis that they also secrete soluble factors that regulate immune responses. Epithelial cells, spleen cells and lymphocytes were obtained from rabbits or rats and cultured in various configurations. Monocytes from rat bone marrow were matured to dendritic cells (DC) ex vivo. Proliferation was measured by [3H]-thymidine incorporation; surface MHC Class II and CD86 using flow cytometry; and mRNA relative abundances using real time RT-PCR. Microporous culture inserts containing rat lacrimal cells inhibited proliferation of rabbit lymphocytes co-cultured with autologous lacrimal cells and of rat lymphocytes co-cultured with TNF-alpha-stimulated DC. They inhibited CD86 and MHC Class II surface expression by maturating DC and reversed surface expression of CD86 but not MHC Class II by partially matured DC. Subsequent exposure of partially matured DC to mediators from rat lacrimal cells reversed the ability to stimulate lymphocyte proliferation. TGF-beta(1) and IL-10 mRNAs increased somewhat when rat lacrimal cells were isolated but decreased markedly in rabbit lacrimal cells. Antibodies to TGF-beta prevented soluble factors from rat lacrimal cells from inhibiting proliferation of rabbit lymphocytes co-cultured with rabbit lacrimal cells, but recombinant TGF-beta alone did not mimic the soluble factors. IL-10 immunopositivity was detected in epithelial cells of interlobular ducts and occasional interstitial cells in rabbit lacrimal gland. Rat lacrimal epithelial cells secrete TGF-beta and other factors that synergize to suppress lymphocyte proliferation and regulate DC maturation. Interlobular duct epithelial cells in rabbit lacrimal glands may express similar functions.
Collapse
Affiliation(s)
- M de Saint Jean
- Department of Physiology & Biophysics, University of Southern California, Los Angeles, CA 90033, USA
| | | | | | | | | | | |
Collapse
|
20
|
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: 302] [Impact Index Per Article: 20.1] [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.
Collapse
Affiliation(s)
- Darlene A Dartt
- Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
| |
Collapse
|
21
|
Cosen-Binker LI, Morris GP, Vanner S, Gaisano HY. Munc18/SNARE proteins’ regulation of exocytosis in guinea pig duodenal Brunner’s gland acini. World J Gastroenterol 2008; 14:2314-22. [PMID: 18416456 PMCID: PMC2705084 DOI: 10.3748/wjg.14.2314] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To examine the molecular mechanism of exocytosis in the Brunner’s gland acinar cell.
METHODS: We used a submucosal preparation of guinea pig duodenal Brunner’s gland acini to visualize the dilation of the ductal lumen in response to cholinergic stimulus. We correlated this to electron microscopy to determine the extent of exocytosis of the mucin-filled vesicles. We then examined the behavior of SNARE and interacting Munc18 proteins by confocal microscopy.
RESULTS: One and 6 &mgr;mol/L carbachol evoked a dose-dependent dilation of Brunner’s gland acini lumen, which correlated to the massive exocytosis of mucin. Munc18c and its cognate SNARE proteins Syntaxin-4 and SNAP-23 were localized to the apical plasma membrane, and upon cholinergic stimulation, Munc18c was displaced into the cytosol leaving Syntaxin-4 and SNAP-23 intact.
CONCLUSION: Physiologic cholinergic stimulation induces Munc18c displacement from the Brunner’s gland acinar apical plasma membrane, which enables apical membrane Syntaxin-4 and SNAP-23 to form a SNARE complex with mucin-filled vesicle SNARE proteins to affect exocytosis.
Collapse
|
22
|
Wang Y, Chiu CT, Nakamura T, Walker AM, Petridou B, Trousdale MD, Hamm-Alvarez SF, Mircheff AK, Schechter JE. Traffic of endogenous, transduced, and endocytosed prolactin in rabbit lacrimal acinar cells. Exp Eye Res 2007; 85:749-61. [PMID: 17904551 PMCID: PMC2190296 DOI: 10.1016/j.exer.2007.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 08/08/2007] [Accepted: 08/16/2007] [Indexed: 11/21/2022]
Abstract
The rabbit lacrimal gland undergoes an immunophysiological transformation during pregnancy, reminiscent of that of the mammary gland as it prepares to deliver secretory IgA into the nascent fluid product. The contents of TGF-beta and prolactin (PRL) within ductal epithelial cells increase, and their primary localizations shift from the apical to the basal cytoplasm, suggesting a transformation from exocrine to paracrine secretion. Studies with ex vivo acinar cell models demonstrated that elevated PRL suppresses traffic of secretory proteins into the regulated exocrine apparatus and directs them into a novel, induced, regulated paracrine apparatus [Wang, Y., Chiu, C.T., Nakamura, T., Walker, A.M., Petridou, B., Trousdale M.D., Hamm-Alvarez S.F., Schechter J.E., Mircheff A.K., 2007. Elevated prolactin redirects secretory vesicle traffic in rabbit lacrimal acinar cells. Am. J. Physiol. Endocrinol. Metab. 292, E1122-E1134]. However, it was not clear whether PRL itself entered the induced paracrine apparatus. In the present study, confocal immunofluorescence microscopy revealed that natively expressed PRL and over-expressed PRL co-localized with PRL receptors (PRLR); rab11, a marker for the recycling endosome; gamma-adaptin, a marker for the Golgi complex and trans-Golgi network; and rab7, a marker for the autophagic lysosomal apparatus. Natively expressed, over-expressed, and endocytosed PRL also co-localized with rab4 and rab5A, markers for the early endosome, and with rab3D, a marker for regulated exocrine secretory vesicles. Endocytosed PRL was stored in intact form and released in response to stimulation with carbachol. Subcellular fractionation analysis detected relative excesses of PRL over PRLR in fractions that contained fragments of the recycling endosome and fractions that contained both secretory vesicle fragments and prelysosomal and autolysosomal fragments. EM-gold microscopy demonstrated PRL within small vesicles, consistent with endosomes or secondary lysosomes, and in large vesicles, consistent with regulated secretory vesicles. The secretory vesicles were preponderantly localized in the apical cytoplasm of control cells, and in the basal cytoplasm of PRL over-expressing cells. These results indicate that when lacrimal epithelial cells synthesize PRL, and when they endocytose it from their ambient medium, they traffic it both into the endosomes that constitute the constitutive transcytotic paracrine apparatus and also into regulated secretory vesicles, which are associated with the exocrine apparatus at low PRL levels and with the induced paracrine apparatus at high PRL levels.
Collapse
Affiliation(s)
- Yanru Wang
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Christopher T. Chiu
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Tamako Nakamura
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Ameae M. Walker
- Division of Biomedical Sciences, University of California, Riverside, CA
| | - Barbara Petridou
- Unité Génomique et Physiologie de la Lactation, Institut National de Recherche Agronomique, 78352 Jouy-en-Josas, France
| | - Melvin D. Trousdale
- Department of Ophthalmology and Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Sarah F. Hamm-Alvarez
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA
- Department of Ophthalmology and Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA
| | - Austin K. Mircheff
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA
- Department of Ophthalmology and Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Joel E. Schechter
- Department of Cell & Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, CA
| |
Collapse
|