Mechanism for Carbachol-Induced Secretion of Lacritin in Cultured Monkey Lacrimal Acinar Cells

Morimoto-Tochigi, Ayumi; Walkup, Ryan D.; Nakajima, Emi; Shearer, Thomas R.; Azuma, Mitsuyoshi

doi:10.1167/iovs.09-4573

Cited by 12 publications

(10 citation statements)

References 46 publications

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“…In rat LG, Cch-induced phosphorylation of p42/44 inhibits secretion [5,17]. In monkey LG, the Cch-induced secretion was found to be independent of p42/44 [16]. The results presented here showed no statistically significant p42/44 phosphorylation by Cch stimulation, even if phosphorylation was observed in some samples.…”

Section: Discussioncontrasting

confidence: 50%

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p38 Mitogen-activated protein kinase modulates exocrine secretion in rabbit lacrimal gland

Carlsson

Gierow

2012

Cellular and Molecular Biology Letters

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Abstract:The lacrimal gland (LG) is an exocrine gland important for secretion of the tear film. The kinase p38 has important signal transduction functions, e.g. in gene transcription, but has previously not been known to modulate exocrine secretion. The aim of the current study was to investigate the role of p38 in carbachol (Cch)-induced LG secretion in LG acinar cells in vitro. Western blotting was used to determine the phosphorylation status of p38 and p42/44 and determine expression of p38 isoforms. To determine the effect of p38 inhibition on LG secretion, PD 169316, a general p38 inhibitor, and SB 239063, an inhibitor of p38α and β, were added to the cells prior to secretion measurements. The results revealed activation of p38 mediated by Cch stimulation and inhibition of Cch-induced secretion as a result of p38 inhibition. The inhibition was observed with PD 169316 isoforms, but not with SB 239063. The p38δ isoform was shown to have robust expression both by Western blotting of acinar cells and immunofluorescence of the whole gland. In conclusion, p38 activation mediates secretion in cholinergic stimulation of rabbit LG cells.

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Section: Discussioncontrasting

confidence: 50%

“…1). Several studies have been performed investigating the role of MAPKs in lacrimal secretion, most of them regarding p42/44 [5,[15][16][17], but also c-Jun N-terminal kinase (JNK) [14]. In rat LG, Cch-induced phosphorylation of p42/44 inhibits secretion [5,17].…”

Section: Discussionmentioning

confidence: 99%

p38 Mitogen-activated protein kinase modulates exocrine secretion in rabbit lacrimal gland

Carlsson

Gierow

2012

Cellular and Molecular Biology Letters

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“…The cholinergic system plays an important role in fluid and electrolyte transport in epithelia. For example, mAChR agonists and antagonists are commonly used to treat impaired saliva and tear secretion (Melvin et al, 2005;Morimoto-Tochigi et al, 2010). However, it is noteworthy that material transport across epithelial cells can be accomplished by either transcellular or paracellular pathways (Tsukita et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

Claudin-4 is required for modulation of paracellular permeability by muscarinic acetylcholine receptor in epithelial cells

Cong

Zhang

et al. 2015

Journal of Cell Science

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The epithelial cholinergic system plays an important role in water, ion and solute transport. Previous studies have shown that activation of muscarinic acetylcholine receptors (mAChRs) regulates paracellular transport of epithelial cells; however, the underlying mechanism is still largely unknown. Here, we found that mAChR activation by carbachol and cevimeline reduced the transepithelial electrical resistance (TER) and increased the permeability of paracellular tracers in rat salivary epithelial SMG-C6 cells. Carbachol induced downregulation and redistribution of claudin-4, but not occludin or ZO-1 (also known as TJP1). Small hairpin RNA (shRNA)-mediated claudin-4 knockdown suppressed, whereas claudin-4 overexpression retained, the TER response to carbachol. Mechanistically, the mAChR-modulated claudin-4 properties and paracellular permeability were triggered by claudin-4 phosphorylation through ERK1/2 (also known as MAPK3 and MAPK1, respectively). Mutagenesis assay demonstrated that S195, but not S199, S203 or S207, of claudin-4, was the target for carbachol. Subsequently, the phosphorylated claudin-4 interacted with β-arrestin2 and triggered claudin-4 internalization through the clathrin-dependent pathway. The internalized claudin-4 was further degraded by ubiquitylation. Taken together, these findings suggested that claudin-4 is required for mAChR-modulated paracellular permeability of epithelial cells through an ERK1/2, β-arrestin2, clathrin and ubiquitin-dependent signaling pathway.

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“…9 For example, in cultured monkey lacrimal acinar cells, we previously reported that acetylcholine analog carbachol (Cch) increased intracellular Ca 2þ , activated the protein kinase C (PKC) pathway, and promoted secretion of the tear protein lacritin. 10 Lacritin protein expression has been detected in primates, and high expression was found in human lacrimal and meibomian glands. 11 Recently, lacritin expression was also found in nonprimate horse tears.…”

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confidence: 99%

“…13 Cholinergic stimulation induced secretion of lacritin from monkey lacrimal acinar cells, suggesting that lacritin is produced in the lacrimal gland and is secreted onto the ocular surface. 10 Since a decrease of tear lacritin was reported in patients with blepharitis 14 and in contact lens-related dry eye, 15 lacritin might play an important role in maintaining tear fluid and the ocular surface. Indeed, lacritin promoted protein secretion from cultured rat acinar cells 16 and stimulated proliferation in cultured human corneal cells and salivary ductal cells.…”

mentioning

confidence: 99%

Lacritin-Induced Secretion of Tear Proteins From Cultured Monkey Lacrimal Acinar Cells

Fujii

Morimoto-Tochigi

Walkup

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. During inflammation of the ocular surface, increased proinflammatory cytokines depress tear protein secretion, suggesting that a decline in lacrimal cell function contributes to dry eye. Lacritin, a glycoprotein secreted from lacrimal acinar cells, may function as an autocrine factor to stimulate tear protein secretion. The purpose of the present experiment was to investigate lacritin-induced protein secretion in normal and cytokine-pretreated (inflammation model) monkey acinar cells.METHODS. Acinar cells from monkey lacrimal glands were cultured with or without tumor necrosis factor alpha (TNF-a) plus interferon gamma (IFN-c). Protein secretion was induced by lacritin or carbachol (Cch, positive control). Proteins were detected and identified by immunoblotting and immunocytochemistry. Intracellular Ca 2þ was measured with the fluorophore Calcium-4, and cell damage was determined by LDH leakage into the culture medium. RESULTS. In cultured monkey acinar cells, lacritin stimulated tear protein secretion in normal cells without elevating intracellular Ca 2þ. In contrast, Cch elevated intracellular Ca 2þ and release of tear proteins. This contrast suggested an alternate, calcium-independent mechanism for lacritin-induced protein secretion. TNF-a plus IFN-c caused LDH leakage from sensitive human corneal epithelial cells, but even higher doses of TNF-a plus IFN-c did not cause LDH leakage from monkey acinar cells, suggesting a higher tolerance against these cytokines. In cytokine-treated acinar cells, lacritin stimulated protein secretion as much as that in normal cells. In contrast, Cch-induced elevation of Ca 2þ and release of proteins were depressed by cytokines.CONCLUSIONS. Lacritin might be a useful biotechnology-based treatment agent against ocular surface diseases where endogenous lacritin is inadequate.

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Mechanism for Carbachol-Induced Secretion of Lacritin in Cultured Monkey Lacrimal Acinar Cells

Abstract: Successful culture of monkey lacrimal acinar cells showed that, among the prevalent tear proteins, the secretion of lacritin involved the PKC/Ca2+ pathway, not the p42/p44 MAPK pathway. Induction of transcription by Cch involved the independent p42/p44 MAPK and PKC pathways.

Cited by 12 publications

References 46 publications

p38 Mitogen-activated protein kinase modulates exocrine secretion in rabbit lacrimal gland

p38 Mitogen-activated protein kinase modulates exocrine secretion in rabbit lacrimal gland

Claudin-4 is required for modulation of paracellular permeability by muscarinic acetylcholine receptor in epithelial cells

Lacritin-Induced Secretion of Tear Proteins From Cultured Monkey Lacrimal Acinar Cells

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